Learn English – There are vs are there

From my personal experience, we never use the word "very" with any verbs although it is labelled as an adverb in the dictionary. Being an adverb simply means that it can be used to describe a verb, an adjective, or an adverb. But at the same time it does not mean that one adverb can be used to describe all three.

Therefore, we won't say I very like/love/hate someone. "Do" in this case is used to add emphasis; however, the equivalent words for "very" in this case are "really," and "truly."

Option B is the correct answer, as your answer key says. The error is in the use of the singular form of the copula "is" with a plural subject.

The correct form of the copula is "are" because the sentence in the non-inverted form is:

Developing the ability to work with others and developing leadership skills are more important than winning.

This is a sentence with a compound subject. That means two subjects, so the plural is used.

Same pattern as:

Trees and bushes are important in gardens.

For clarification, here is the same sentence with the corrected word and with brackets added to contain each subject:

[I returned here to edit brace to brackets and cartouche to contain. I cannot believe I would have used the terms braces and cartouche here.

More important than winning are { developing the ability to work with others } and { developing leadership skills }