Let's find the base first.
9*24*1/2 = 9*12 = 108
Now we multiply that by 2, as there are 2 triangles.
108*2 = 216
We'll find the 15 by 20 side next.
15 * 20 = 300.
Multiply that by 2, as there are 2 rectangles of those dimensions.
300*2 = 600
The last side is the 24 by 20 side.
24*20 is 480.
There's only one of those rectangles, so we won't multiply it by 2.
Now, we'll add all of our areas together.
216+600+480 = 1296.
Therefore the answer is A, 1296 in^2.
Hope that helps! :)