Please help me 8th grade math test

1. What is the difference between their volumes? Round your final answer to the nearest tenth.

a)7.3 inches b)6.7 inches c)6.3 inches d)5.7 inches( this will be the first picture)

4. Bo is making a step stool for his bathroom sink that is shaped like a rectangular prism.(second image)

What is the total surface area of the step stool?

a)6 3/4 b)4 1/2 c)5 d)5 3/4