The formula for distinguishing the volume of a rectangular prism is the Base being multiplied by the Height. In other words, the formula is:
V = Bh
Now, we need to substitute our values for each variable to solve for our volume.
V = 5 x 10.5; multiply the two numbers.
V = 52.5.
Your answer for this is "C.) 52 1/2" (as "52.5" is equivalent to "52 1/2").
I hope this helps!