'That' is A, a demonstrative pronoun. Because you are referring to that person, you are basically pointing at your cousin, therefore it must be a demonstrative pronoun.
B: to provide several possible anwser
MUDA MUDA MUDA MUDA MUDA MUDA MUDA MUDA MUDA MUDA MUDA MUDA MUDA MUDA MUDA MUDA MUDAAAAAAAAA
I would say D, as it would allow the reader to understand the comparison being made
