Choose the correct interrogative form:

1. Interrogative Sentence Structure: In English, interrogative sentences are formed by inverting the subject and the auxiliary verb (if present) or the main verb. This inversion happens to create a question.

2. Tense Usage in Questions: The choice of tense in a question depends on the time frame of the action or event being asked about.

Now, let's analyze the options:

ক - When did you born?

- This sentence is not grammatically correct. The correct structure for a past tense question about the time of birth should use the auxiliary verb "were" instead of "did."

খ - When were you born?

- This is the correct option. It follows the rule of using the past tense "were" for questions about the time of birth. The subject "you" and the past participle "born" are in the correct order, forming a grammatically accurate question.

গ - When are you born?

- This sentence is grammatically incorrect. It uses the present tense "are" instead of the past tense "were" to inquire about the time of birth.

ঘ - When you born?

- This sentence is not in the correct structure for an interrogative sentence. It lacks inversion, where the auxiliary verb "were" should come before the subject "you" to form a question.

Therefore, the correct choice is খ - When were you born?, as it follows the rule of using the past tense "were" for questions about the time of birth and maintains the correct interrogative sentence structure.