What letter comes next in the series: z, x, v, t, ?

A. S

If X * Y means X is the mother of Y, and Y + Z means Y is the brother of Z, what is the relationship between X and Z?

A. GRANDMOTHER

If P ÷ Q means P is the father of Q, and Q - R means Q is the sister of R, what is the relationship between P and R?

B. UNCLE

What character should replace the question mark in the sequence 3, 6, 9, ?, 15?

B. 12

Complete the series: m, n, o, p, ?

A. Q