Let's analyze the given series: GASM, CCOO, YEKQ, ?, QICU.
We'll look at the pattern in the letters of each term:
1) First letter pattern (G, C, Y, ?, Q):
· G → C: Move 4 steps backward (G → F → E → D → C)
· C → Y: Move 4 steps backward (C → B → A → Z → Y)
· To continue this pattern: Y → U (Y → X → W → V → U, 4 steps backward)
So, the first letter of the missing term is U.
2) Second letter pattern (A, C, E, ?, I):
· A → C: Move 2 steps forward (A → B → C)
· C → E: Move 2 steps forward (C → D → E)
· To continue this pattern: E → G (E → F → G, 2 steps forward)
So, the second letter of the missing term is G.
3) Third letter pattern (S, O, K, ?, C):
· S → O: Move 4 steps backward (S → R → Q → P → O)
· O → K: Move 4 steps backward (O → N → M → L → K)
· To continue this pattern: K → G (K → J → I → H → G, 4 steps backward)
So, the third letter of the missing term is G.
4) Fourth letter pattern (M, O, Q, ?, U):
· M → O: Move 2 steps forward (M → N → O)
· O → Q: Move 2 steps forward (O → P → Q)
· To continue this pattern: Q → S (Q → R → S, 2 steps forward)
So, the fourth letter of the missing term is S.
Conclusion:
The missing term is UGGS, which matches option (a).
Thus, the correct answer is a) UGGS