装饰用木材分为针叶树与阔叶树，下列( )是针叶树。

A．红松、杉木、水曲柳、马尾松

B．蚁木、橡木、甘巴豆、柚木

C．红松、马尾松、杉木、柏树

D．马尾松、落叶松、柞木

—Are you free after school?

—Sorry. I’ve planned to treat a friend of mine to dinner ________for his help.

A．in addition

B．in turn

C．in return

D．in total