Step-by-step Solution:

Pattern Analysis

This series contains three independent patterns:

• 
  First Letter (Q, S, U, W, ...): This sequence moves forward by 2 letters at each step. The letter after W is Y.
  


• 
  Number (1, 2, 6, 21, ...): This sequence follows the rule (previous number × n) + n, where 'n' starts at 1 and increments. The next number is (21 × 4) + 4 = 88.
  


• 
  Last Letter (F, E, D, C, ...): This sequence moves backward by 1 letter at each step. The letter after C is B.
  

Combining these results (Y, 88, B) gives the next term.

Final Answer: The correct option is C. Y88B