A rain barrow that can hold up to 275 gallons of water is initially empty when it begins to fill with rain water at an average rate of 15 gallons a week. Which expression correctly expresses the volume of water in the tank V, in gallons, after w weeks?
A. V + 15w = 275
B. V = 275 - 15w
C. 275-15V = w
D. V = 15w
