Select the option that can replace the question mark (?) in the given series.

E, F, H, K, ?

Given: E, F, H, K, ?

Logic: Difference between letters are increasing + 1, + 2, + 3 and + 4.

E + 1 → F

F + 2 → H

H + 3 → K

K + 4 → O

So, the missing term is O.

Thus, correct option is (b).