Complete the series: B, D, F, H, ?

A. J

In a family, there are three children: X, Y, and Z. X is the brother of Y, and Y is the sister of Z. How is Z related to X?

A. BROTHER

A is married to B. They have two children, C and D. C is a doctor, and D is a teacher. If B is a lawyer, what is the profession of A?

D. UNKNOWN

If K is the grandmother of L, and L is the son of M, what is the relationship of M to K?

C. DAUGHTER-IN-LAW

What is the next letter in the series: A, E, I, M, ?

A. O