4. In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it? a _ c a a b _ a _ b c a a b _ a _ b _ a
5. In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it? a _ c a a b _ a _ b c a a b _ a _ b _ a
10. In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it? W_YZ_X_ZW_Y_