Hello.
The Answer: A. 300 ft^2
Step-by-step explanation: Find the area of two sides (Length*Height)*2 sides.
Find the area of adjacent sides (Width*Height)*2 sides.
Find the area of ends (Length*Width)*2 ends.
Add the three areas together to find the surface area.
Formula: A= 2( W l + H L + H W)
Have a nice day.