The elements A,B,C,D,E have atomic numbers 9, 11, 17, 12and 13. Which elements belong to the same group?

Q. The elements A,B,C,D,E have atomic numbers 9, 11, 17, 12and 13. Which elements belong to the same group?

A.            A and B

B.            B and D

C.            A and C

D.            D and E

Answer: A and B