Can you please explain this sir

"Though the group can do without the clarinet player for their upcoming performance, the drummer is (i) ______ ."
- "Though" signals a contrast.
- The clarinet player is not needed ("can do without").
- Therefore, the drummer must be the opposite: essential, indispensable, absolutely needed.

Examining choices:
- A. important - fits, but somewhat mild. Being "important" is the opposite of "can do without," but is there a stronger word?
- B. vital - absolutely essential, indispensable. Stronger and more precise contrast to "can do without." Fits perfectly.
- C. dependable - reliable. Not directly about necessity; you can depend on someone you don't strictly need.
- D. unnecessary - opposite of what's needed; this would mean no contrast.
- E. present - merely being there isn't the contrast to being needed.

Answer: B. vital