Subtract (3 + 2i) from (–9 – 8i).

Subtract by changing the signs of both terms in (3 + 2i): (–9 – 8i) – (3 + 2i) = –9 – 8i – 3 – 2i. Combine real parts and imaginary parts separately to get –12 – 10i, which is choice C.

AI-written and checked against the verified answer.