Two interleaved series, but placement is irregular: Series 1 (Positions 1, 4, 7, 10...): A, B, C, ... Next is D (at position 10). Series 2 (Positions 2, 3, 5, 6, 8, 9...): Z(26), X(24), V(22), T(20), R(18), ... Pattern is-2. Next is P(16) (at position 9). The missing terms are P (at 9th) and D (at 10th). This matches option (3).