your shirt looks nice.Is it ----cotton?

your shirt looks nice.Is it ____cotton?
--Your shirt looks nice.Is it ____cotton?
--Yes.And it's____Ningbo.
A.made from;made by
B.made for;made in
C.made of;made in
D.made of;made by
为什么?
我书上的正确答案是C,但是我很奇怪为什么用made of而不是made from?