Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series. L_UA_Z_N_AP_L_U_PZ

N, L, P, A, N, U, Z N, P, L, U, Z, N, A P, L, U, Z, N, A, N P, N, L, Z, U, A, N

N, P, L, U, Z, N, A

L N U A P Z / L N U A P Z / L N U A P Z N, P, L, U, Z, N, A