The professor had a big nose, . . . . . . . . small mouth and . . . . . . . . enormous mustache. A. the, an B. a, an C. an, the D. the, a

The correct answer is A. the, an.

The professor had a big nose, an enormous mustache, and a small mouth. The professor is a specific person, so we use the definite article “the” before “nose.” The mustache is also a specific thing, so we use the definite article “the” before “mustache.” The mouth is not a specific thing, so we use the indefinite article “an” before “mouth.”

Here is a more detailed explanation of each option:

• Option A: the, an. This is the correct answer. The professor is a specific person, so we use the definite article “the” before “nose.” The mustache is also a specific thing, so we use the definite article “the” before “mustache.” The mouth is not a specific thing, so we use the indefinite article “an” before “mouth.”
• Option B: a, an. This is not the correct answer. The professor is a specific person, so we should not use the indefinite article “a” before “nose.” The mustache is also a specific thing, so we should not use the indefinite article “a” before “mustache.” The mouth is not a specific thing, so we should use the indefinite article “an” before “mouth.”
• Option C: an, the. This is not the correct answer. The professor is a specific person, so we should not use the indefinite article “an” before “nose.” The mustache is a specific thing, so we should use the definite article “the” before “mustache.” The mouth is not a specific thing, so we should use the indefinite article “an” before “mouth.”
• Option D: the, a. This is not the correct answer. The professor is a specific person, so we should not use the indefinite article “a” before “nose.” The mustache is a specific thing, so we should use the definite article “the” before “mustache.” The mouth is not a specific thing, so we should use the indefinite article “an” before “mouth.”