Select the term that can replace the question mark (?) in the following series.

AC , CF , EJ , GO , ?

Series-AC , CF , EJ , GO , ? 

Logic: The sequence advances by adding 2 to the first letter and 3, 4, 5, and 6 sequentially to the second letter.

A+2=C, C+3 = F 

C+2 =E, F+4 = J

E+2 =G, J+5 = O

G+2 = I, O +6 = U 

IU, is the correct answer 

Thus, correct answer is (a) IU