A. Working took place in the past. (A period of time is implied, of course, since you had to work for a period of time, but that fact isn't specified in this tense usage.)
B. Similar to A, but working took place over an unspecified period of time in the past.
C. Working took place over a period of time in the past. The tense specifies that there is a time also in the past that the period ended. (In your sentence, "until" is the wrong preposition; "before" is correct. Also, "before today" must imply "before your termination today"--which it does--to be correct.)
D. Working took place over an unspecified period of time in the past. My answer to C also applies here.
E. The person is still working here, and you want to know when he started. This isn't consistent with your scenario, so presumably that's why you don't feel comfortable with it. :)
F. It would be correct if the person isn't yet seeing his employment as being in the past. ("I have been working here for six years, and I'll be darned if I give up my job without a fight." would be an obviously correct usage, for example.) Once the person understands himself to be terminated, he had been working here for six years (when he was terminated).
G. Yes, I agree. "for the past six years" (or more often "for the last six years") should be used as "I have been working here for the past six years."
The package can be torn open...
Open is an adjective complement to the verb tear: it designates the state which the action of the verb effects in the package. Tearing the package causes it to be open.
In the 'canonical' active form of this sentence the package would be the object, so open is often called an 'object complement' or 'object-oriented complement':
He tore [objthe package] [compopen].
But your example is cast in the passive voice, and the canonical-form 'object' is cast as subject, so the term 'object complement' is misleading. Let's call it a 'Patient complement' instead, with 'Patient' designating the object which is acted upon.
With many verbs a Patient complement is obligatory—causative make, for instance, or verbs of caused motion. Depending on the verb the complement may be an adjective phrase, a preposition phrase, or a noun phrase:
He makes [objJanet] [comphappy].
She put [objthe teacup] [compon the shelf].
The company named [objHenderson] [compCEO].
Many other verbs do not require a Patient complement but do take one freely—tear in your example, for instance. Such optional complements are often called 'secondary complements' (but the scope of that term varies with different authorities).
Patient complements are of course only possible with transitive verbs—verbs which take a Patient as an object in canonical-form sentences. Intransitive verbs often take Agent complements, complements which designate a state present or effected in the subject Agent:
He has risen [compvery high].
John flew [compto New York] last night.
Ancient Greek athletes competed [compnaked].
Best Answer
Use newly. This refers to the recency of the manufacturing of the disk.
If you use new you are refering to it as a "manufactured disk" as opposed to "handcrafted disk" or "homemade disk" or however else a disk might be produced/created.