A close up of a keyboardDescription automatically generated
According to the positional values of the alphabets,
1) O14A → O = 15, A = 1 → 15 - 1 = 14
2) P14B → P = 16, B = 2 → 16 - 2 = 14
3) Z22D → Z = 26, D = 4 → 26 - 4 = 22
4) U20H → U = 21 , H = 8 → 21 - 8 = 13
Hence, the odd one among the given options is U20H.