1. 

What should come in the place of question mark (?) in the following alpha numeric series?

B 2 I 9 R 18 T 20 H ?

A. 6
B. 7
C. 8
D. 9

Answer: Option C

Explanation:

Hence, the letters are followed by numbers, which denotes is positional value in English alphabet.

letter-and-symbol-series-logical-reasoning-practice-level---letter-and symbol-series-problems

Hence, the missing term is 8.