What orbitals overlap to create the C-O bond in CH3OH?

Question

A. sp3-sp3
B. s-sp3
C. s-p
D. sp2-sp3
E. s-sp2

I know the answer is A because it's on a practice test and the answers are circled but I have no idea why it is that way. Please explain.

Answer 1

http://books.google.com/books?id=jcn6sgt7RpoC&pg=PA413&lpg=PA413&dq=orbital+overlap+CH3OH&source=bl&ots=0BR74RQzcs&sig=tw2ZkQBR0zzQ4LM1IEUBCPM3aSA&hl=en#v=onepage&q=orbital%20overlap%20CH3OH&f=false