Contrary to popular belief, video games aren‘t just for killing an idle Thursday evening, in fact, a variety of recent studies have begun to demonstrate their teaching potential.

A. video games aren‘t just for killing an idle Thursday evening, in fact, a variety of recent studies have begun to demonstrate
B. video games aren‘t just to kill an idle Thursday evening, but a variety of recent studies, in fact, have begun to demonstrate
C. video games aren‘t just for killing an idle Thursday evening; in fact, a variety of recent studies has begun to demonstrate
D. video games aren‘t just for killing an idle Thursday evening; in fact, a variety of recent studies have begun to demonstrate
E. video games aren‘t just for killing an idle Thursday evening, and a variety of recent studies have begun in demonstration of

wow great explanation ! thank you!

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The issue must be between A or D...

A and D differ by the use of semi colon here.
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My answer would also be D.

I would say that A is a run-on sentence. The comma is not sufficient to connect the two main clauses; however, a semicolon solve this problem.

I would also say that "Video games" is clearly the subject in the first clause making "their" unambiguous. What else could be the antecedent?

I think it should be A....I'm confused as well, the second clause is dependent on the first one because of the pronoun "their"

The independence of clauses in ; usage allows use of pronouns. Think about it, if there were no correlation between the two clauses, the punctuation may well be a . (fullstop/period). Presence of pronouns should not be considered while deciding independence of clauses.

Crick

Clauses are "dependent" or "independent" only based on the presence of a main subject and main verb. Here we have "games aren't," a subject and a verb, neither one subordinated by a relative pronoun, preposition, or subordinating conjunction, so they are a Main Subject and a Main Verb. Later, we have "variety ... has begun," another subject and verb, again Main Subject & Verb because they are not subordinated. Two independent clauses require either a semicolon or a coordinating conjunction (FANBOYS).

Furthermore, the verb cannot be "have" in the second clause; the subject is "variety." Remember, anything following a preposition, such as "of," is NEVER the main subject of anything. "recent studies" is the object of "of," not the subject of "have begun."

In terms of pronouns, pronoun ambiguity only has to do with whether or not there is one clear logical antecedent, agreeing in number with the pronoun. An ambiguous pronoun does not make a sentence "dependent." Take, for example, the following paragraph:

"I am really happy with my GMAT tutor. He is professional and knowledgeable and on time and knows a lot about the test. I am thankful for this, because it is a difficult test."

All three sentences are clearly complete sentences and fully independent clauses. "He" in the second sentence refers to "tutor," and "it" in the third refers to "test." Obviously on the GMAT this never happens, since Sentence Correction only tests single sentences. However, the moral of the story is that, in English grammar, pronouns do not have to have their antecedents in the same sentence or clause.
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Adam
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Thanks for this explanation, Adam!

I had a doubt.. Since variety is a quantity and for quantities the object of the prep phrase is treated as the subject, (eg: A number of students ARE...) the verb must be "have" since studies is plural. Can you please explain this?

Thanks!!

First i picked c later i found where i was wrong& my mistakes.............