![](https://cos-cdn.shuashuati.com/pipixue-web/2020-1231-2005-12/ti_inject-812ce.png)
If a firm spends $600 on advertising, its
A.
ATC and MC curves shift upward.
B.
MC curve shifts upward and its ATC curve does not shift.
C.
ATC curve shifts upward and its MC curve does not shift.
D.
ATC curve shifts upward and its MC curve shifts downward.