The logic follows here is :- The sum of the 1st number and 3rd number = The place value of the middle letter. Given series : 4S15, 3W20, 16S3, 15Q2, ? 4S15 → 4 + 15 = 19 (S) 3W20 → 3 + 20 = 23 (W) 16S3 → 16 + 3 = 19 (S) 15Q2 → 15 + 2 = 17 (Q) Similarly, 14N0 → 14 + 0 = 14 (N) Hence, the correct answer is "14N0".