Topic: Article,

Best Answer Explained in Below-:

The correct choice for the sentence '__ great many students attended the test.' is 'C) A.' The article "a" is used before singular nouns that begin with a consonant sound, and it implies any one of a category – in this case, it refers to an unspecified quantity of students.

The phrase "a great many" is an idiomatic expression in English that means a large number or a significant amount. It combines the indefinite article "a" with "great many," emphasizing that we are discussing a large, but not specifically quantified, subset of students.

Using "The" (option A) would imply that we are referring to a specific great many students, which doesn't fit well with the intended meaning. "An" (option B) is used before singular nouns that start with a vowel sound and is not appropriate here as "great" starts with a consonant sound. "None of them" (option D) does not apply as we need an article to complete the sentence grammatically.

Therefore, "a" correctly fits the context of the sentence, leading to the conclusion that 'C' is the right answer.