pls help ur girl out

A lamppost, CAB, bent at point A after a storm. The tip of the lamppost touched the ground at point C, as shown in the image attached.

What is the height, in feet, of the portion AB of the lamppost?

A) 12 tan 45°

B) 12 divided by tan 45 degrees

C) 12 divided by cos 45 degrees

D) 12 cos 45°

this is a FINAL EXAM!!!!! please answer if you know the answer :) wrong answers will be reported