Correct option is D
Given:
NOR → 2-3-6
Logic: The code is obtained by subtracting 12 from the alphabetical position of letters after M.

Explanation:
NOR
N = 14 → 14 − 12 = 2
O = 15 → 15 − 12 = 3
R = 18 → 18 − 12 = 6
N = 14 → 14 − 12 = 2
O = 15 → 15 − 12 = 3
R = 18 → 18 − 12 = 6
So, NOR → 2-3-6
REST
R = 18 → 18 − 12 = 6
E = 5 (31) - 12 → 19
S = 19 → 19 − 12 = 7
T = 20 → 20 − 12 = 8
R = 18 → 18 − 12 = 6
E = 5 (31) - 12 → 19
S = 19 → 19 − 12 = 7
T = 20 → 20 − 12 = 8
REST → 6-19-7-8
Thus, the correct option is (d).