Correct Answer - Option 4 : OMSVY
Pattern: The letters in each set of elements have been succeeded by three places.
1. CFILO
C + 3 = F, F + 3 = I, I + 3 = L, L + 3 = O
2. UXADG
U + 3 = X, X + 3 = A, A + 3 = D, D + 3 = G
3. ORUXA
O + 3 = R, R + 3 = U, U + 3 = X, X + 3 = A
4. OMSVY
O + 3 = R (not M), R + 3 = U (not S), U + 3 = X (not V), X + 3 = A (not Y)
Thus, OMSVY is odd among the options.
Hence, OMSVY is correct.