Select the option that can replace the question mark (?) in the following series.
VO39, TM35, RK31, PI27, ?

Given: VO39, TM35, RK31, PI27, ?

Explanation: First letter place value decrease by -2, Second letter place value decrease by -2 and the number is decrease by -4

First letter: V-2= T, T-2= R, R-2=P, P-2=N

Second letter: O-2=M, M-2=K, K-2=I, I-2= G

Number: 39-4=35, 35-4=31, 31-4=27, 27-4=23

So the ? is replaced by NG23

Thus, correct option is (b).