Fill in the blank with appropriate Modal: You _______ obey your paren…

The correct answer is Option (1) → Should

Note: The given answer is as per the official NTA Answer Key. However, more than one answer is possible here: Option (1) "Should", Option (2) "Must" and Option (4) "Ought to" all make a correct sentence, as explained below.

Option 1: Should — Correct (Answer as per NTA).

• Should expresses moral duty or what is right to do.
• Obeying one's parents is a duty, so "You should obey your parents" is the usual sentence.
  Example: We should respect our elders.

Complete sentence: You should obey your parents.

Option 2: Must — Can also be considered as correct.

• Must expresses strong obligation or necessity.
• "You must obey your parents" is grammatical and natural; it states the duty more firmly, like a rule.
  Example: You must wear a helmet while riding a scooter.

Option 3: Can — Incorrect.

• Can expresses ability or permission.
• "You can obey your parents" only says that obeying them is possible; it does not express the duty the sentence calls for.
  Example: She can speak three languages.

Option 4: Ought to — Can also be considered as correct. Ought to has the same meaning as should, moral duty: "You ought to obey your parents" is equally correct.
Example: You ought to apologise to your friend.