单项选择题

W: I could not recognize Sam after he got that new job. lie’s always in a suit and a tie now.
M: Yeah, he was never like that at college. Back then he went around in an old T-shirt and jeans.

What can we learn about Sam()。

A. He dresses very casually now.
B. He has just got a promotion.
C. He has changed his job recently.
D. He used to dress formally at collage.