Patti's Pet Palace has an 85-gallon fish tank. When it needs to be cleaned, it can be drained at a rate of 2 gallons per minute. Assuming the tank was full, and x represents the number of minutes the tank has been draining, which of the following equations represents the amount of water in the tank after x minutes?
A.
y = 85x - 2
B.
y = 2x + 85
C.
y = 2x - 85
D.
y = 85 - 2x