Answer:
942 cubic feet
Step-by-step explanation:
Here's a tip Subtracting a fraction is the same as multiplying it's reciprocal so for 3/4 - 3/8 you can do 3/4 x 8/3. Multiplying its reciprocal mean turn the 2nd fraction around
By using dimensional analysis, this problem can be simple.

B
The second one is the right answer