What do TEU and FEU mean（）

A. TEU= Forty-foot equivalent unit; FEU= Twenty-foot equivalent unit

B. TEU= Twenty-foot equivalent unit; FEU= Forty-foot equivalent unit

C. TEU= Fourteen-foot equivalent unit; FEU= Twelve-foot equivalent unit

D. TEU= Twelve-foot equivalent unit; FEU= Fourteen-foot equivalent unit