APU exhaust is _____(沿管道流动/输送) overboard through the _____（尾锥）ta

APU exhaust is _____(沿管道流动/输送) overboard through the _____（尾锥）tail cone of the airplane. What is the part of speech of "duct"?

A.ducted， cone

B.duct, tail

C.pipe, taicone

D.ducted, tailcone

正确答案是D