영어 어법 문제 답과 해석 부탁드려요

영어 어법 문제인데 답과 해석을 알려주세요.

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.

선택지는 ① though - produce - themselves ② though - producing - them ③ despite - producing - them ④ despite - produce - themselves ⑤ despite - produce - them 입니다.
답이 despite라고 하는데 이유를 잘 모르겠어요.