What letter comes next in the series: b, d, f, h, ?

A. J

If two students, Mark and Lucy, interchange their ranks in a group of 40 students where Mark is 10th from the top and Lucy is 31st from the bottom, what will be Mark's new rank from the bottom after the interchange?

A. 30TH

N is the grandfather of O. P is the father of O. How is N related to P?

B. FATHER

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

A. Q

In a group of 25 people, if Tom is ranked 8th from the top and 18th from the bottom, how many people are there in total?

B. 25