Answer:
The answer is D) 13.9
Explanation:
Since the angle of elevation is adjacent to the length of 24, than to find the height you have to use tangent. so you take your calculator in DEGREES mode and enter tan(30) which gives you =0.5773502692... than you would multiply by 24 which gives you the height =13.8564.....
Sorry if I wasn't specific enough, ask if you want more help. I am sure this is the right answer