(B) is perfectly correct in either American or British English. Take a look at this example from the Cambridge Dictionaries Online:
A total of 21 horses were entered for the race.
(C) is also correct, as ten babies is explicitly plural, and should thus take the plural are.
(A) is not correct because the collective noun total should always be treated in the plural sense when
- it is explicitly used with the word, number, or the word, number, is implied (in a strict sense*),
- the items being counted are identified/clarified/specified, AND
- the size of the number is given.
In the following examples, all conditions are satisfied:
- A total of number of 3500 students were at the seminar. [Plural]
- A total [number] of 11 shells are in my possession. [Plural]
In this example, conditions (1) and (2) are satisfied, but condition (3) isn't:
- The total number of students in attendance was unbelievably large. [Singular]
In the first sentence of this example, only condition (3) is satisfied, while none of the conditions is satisfied in the second sentence:
- My total is 11. Theirs is much higher. [Singular]
Finally, in this case, condition (1) is not satisfied:
- 'How many pennies do we now have?' 'The current total is 22.' [Singular]
Thus, total should be treated as singular whenever these conditions are not satisfied at the same time. (This rule should not be applied with the construction There is/are.)
The agreement between nouns (collective, in this case) and verbs is called concord and much has been published on its often confusing rules of usage. The most interesting and informative article I found in the course of answering this question, was "Concord", by Marianne Drennan. (It is of South African origin, so it is likely closer to British English but, excellent article nonetheless.)
Also of note is the pronounced difference in the treatment of collective nouns between British and American English. Some collective nouns are mostly treated as singular in American English but often considered plural in British English. Two quick examples are team and family. See this note on grammar at Oxford Dictionaries Online for more information on this phenomenon. The treatment of total, however, transcends this analysis for the most part. Consider, however, another interesting example provided, in part, by the asker (@xport):
- There are ten babies. [Universally correct]
- There are ten babies in total. [Universally correct]
- There are a total of ten babies. [Plural. British?]
- There is a total of ten babies. [Singular. American?]
I'm not sure if the British/American analysis holds here, as one would find both forms (there is/there are) widely used. There are certainly sounds better, but some would argue that there is is more correct, because, strictly speaking, total by itself should be a singular noun. ("Says who?" others may counter!) Consider this, though:
There is/are a total number of ten babies. [?!]
I will not comment on this. Suffice it to say that this worrisome situation can always be avoided.
**in a strict sense* since the word, total, always involves a number, anyway. Try to see if you can insert the word number into your sentence (if it isn't already there) without losing the intended meaning. If this can be done, then it means the word, number is implied.
Best Answer
When referring to amounts of objects as opposed to the objects themselves, you normally use singular agreement. This has nothing to do with fractional amounts, and nothing to do with the use of 'a total of', but is a property of amounts in general.
We can see this when use anaphora to refer to the amount.
As TimLymington points out in the comments, there are some interesting wrinkles in this, although they simply confirm the statement above. Fractions always control plural number within the noun phrase, but whether that noun phrase will control plural verbal agreement depends on whether it refers to a measure or the objects themselves. So in the example below, plural agreement is used (not singular) because the noun phrase "0.5 apples" refers to actual apples and not to a measure.
We can see this more clearly with the following examples, which don't use fractions.
In the first example, we are referring to the actual potatoes, and so the agreement is plural. Singular is marginally possible if we are referring to the measure. In the second example we are referring to the measure, and agreement is singular.