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

Triangle ABC has measure of angle C equal to 50 degrees, measure of angle ABC equal to 90 degrees, and length of BC equal to 10 feet.

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

10 divided by tan 50 degrees
10 divided by cos 50 degrees
10 cos 50°
10 tan 50°