Select the correct sentence. If you come from a happy family, one should be thankful. If a person comes from a happy family, you should be thankful. If a person comes from a happy family, he should be thankful.

Answer :

Answer: The third one

If a person comes from a happy family, he should be thankful.

Answer: If a person comes from a happy family, he should be thankful.

Explanation: It is the only one with correct grammar.