Explanation:

The correct answer is option 'C' - studies.

Here's the explanation:

In the sentence, the subject is "he" and the verb is "study." The question is asking whether "he" studies daily or not.

To answer this question, we need to use the present simple tense because the action of studying daily is a habit or a routine. The present simple tense is used to talk about regular or repeated actions, habits, general truths, and permanent situations.

In the present simple tense, we add an "-s" or "-es" to the base form of the verb when the subject is a singular third-person pronoun (he, she, it).

For example:
- I study every day.
- You study every day.
- He studies every day.
- She studies every day.
- It studies every day.
- We study every day.
- They study every day.

In the given sentence, the subject "he" is a singular third-person pronoun, so we need to use the base form of the verb "study" with an "-s" added to it. Therefore, the correct answer is "studies."

The other options are incorrect:
- Option 'A' - study: This is the base form of the verb and does not match the subject "he."
- Option 'B' - will study: This is the future tense and does not match the question, which is asking about a present habit.
- Option 'D' - studied: This is the past tense and does not match the question, which is asking about a present habit.

Summary:

The correct answer is option 'C' - studies. In the present simple tense, when the subject is a singular third-person pronoun, we add an "-s" or "-es" to the base form of the verb. Therefore, the correct sentence is "Yes, he studies daily."