Answer : 1. "15O16"
Explanation :

Answer: A) 15O16 Explanation: The first digit is formed by adding the numbers which are the results of powers of 2 increased by one and second letter is the corresponding alphabet to that number...last number is the next number to the first one...therefore 15=7+8 (i.e. 2^3) O is corresponding alphabet to 15 and 16 comes after 15