静脉曲张型溃疡的主要病因是（）。

A.深静脉回流不畅

B.深静脉栓塞

C.静脉曲张

D.足癣等引起感染

E.淋巴回流障碍

—Do you like the red car ______ is made in Tianjin?

—Sure, it looks terrific. [ ]

A. where

B. who

C. which

D. when