Have vehicles gotten more fuel-efficient over the years? Between 1960 and 1999 the size and shape of automobiles in the United States has changed almost annually. The amount of fuel consumed by these vehicles has also changed. The following table describes the average fuel consumption per year per passenger car in gallons of gasoline. Year, t 1960 1970 1980 1990 1995 1997 1998 1999 Gallons Consumed Per Passenger Car 668 760 576 520 530 538 544 552 Determine the average rate of change, in gallons of gas per year, from 1960 and 1999 and then determine what the result means in this situation. a. -0.33gal/year; the average fuel consumption per year of a passenger car in the U. S. decreased by a third of a gallon per year. b. 0.33 gal/year; the average fuel consumption per year of a passenger car in the U. S. increased by a third of a gallon per year. c. 2.97 gal/year; the average fuel consumption per year of a passenger car in the U. S. increased by nearly 3 gal/year. d. -2.97 gal/year; the average fuel consumption per year of a passenger car in the U. S. decreased by nearly 3 gal/year.