Rajasthan Police Constable Model Paper 9

The series follows the following pattern.
P + 2 = R, R - 3 = O, O + 4 = S, S - 5 = N.
And, 1 + 3 = 4, 4 + 4 = 8, 8 + 5 = 13, 13 + 6 = 19.
A + 3 = D, D + 4 = H, H + 5 = M, M + 6 = S.
Hence, N19S is the correct answer.