If Henry were to add 4 gallons of water to a tank that is already 3/4 full of water, the tank would be 7/8 full. How many gallons of water would the tank hold if it were full?
Choose the correct choice from the following:
A) 32
B) 40
C) 64
D) 80
E) 96

Rationale: "7 / 8 x - 3 / 4 x = 4 galls 1 / 8 * x = 4 gallons x = 32 gallons answer a"
Answer: A