어법 문제 정답과 해석 부탁드려요

다음 문장에서 (A), (B), (C)에 들어갈 표현과 해석이 궁금합니다.
Not all insects are enemies of man. The silkworm spins threads of silk, which (A) [despite / though] the popularity of synthetic fabrics is still an important textile material. In addition to (B) [produce / producing] honey, the honeybee help farmers grow fruits, vegetables, and grains by pollinating their flowers. Also other insects such as ladybirds, beetles, etc. prey upon our insect enemies and thus help us to keep (C) [them / themselves] under control.
(A) despite가 답이라고 하는데 이유를 잘 모르겠어요.