The graph shows the relationship between the distance a car is driven and the number of gallons of gasoline used. Identify the value in d in the point (1, d). What does that point represent?
A. d=25; the unit rate is 25 miles per gallon
B. d=25; the unit rate is 25 gallons per mile
C. d=50; the unit rate is 50 miles per gallon
D. d=50; the unit rate is 50 gallons per mile
