A watering can dispenses water at the rate of 0.25 gallon per minute. The original volume of water in the can was 6 gallons. Which set of ordered pairs shows the volume of water in the can in gallons (y), as a function of time in minutes (x), from the first minute after the can starts dispensing water?

{(1, 6.0), (2, 5.75), (3, 5.50)}
{(6.0, 1), (5.75, 2), (5.50, 3)}
{(1, 5.75), (2, 5.50), (3, 5.25)}
{(5.75, 1), (5.50, 2), (5.25, 3)}