Explanation

The average fuel efficiency of vehicles sold nationwide during the period 2000- 2004 was 25 miles per gallon; the corresponding figure during the period 1995- 1999 was 20 miles per gallon. The national average price of gasoline during the period 2000-2004 was $2 per gallon; the corresponding figure during the period 1995-1999 was $1.60 per gallon.

The statements above, if true, best support which of the following conclusions?

A) The average fuel efficiency of vehicles sold nationwide should reach 30 miles per gallon for the period 2005-2009.
We cant say this based on what is given in the argument

B) The national average price of gasoline during 1997 was lower than the corresponding price during 2003.
We are given a range of years and do not have any information about individual years and how low or high they were relative to the average they are part of

C) Rising gasoline prices led consumers to purchase more fuel-efficient cars.
*could be true*. Let's keep this aside and make sure that D and E can be totally eliminated

D) Between the two described time periods, the national average fuel efficiency and the national average gasoline price both increased at roughly the same rate. 5/20=1/4 (Fuel Efficiency). 0.4/1.6=1/4 (Price of Gasoline). Yes, we can very confidently say this without any doubt. C is thus eliminated as D is a stronger choice

E) Consumers spent more money on gasoline during the period 2000-2004 than during the period 1995-1999.
We can't say this. Maybe consumers stopped putting miles on their milometer and on the contrary saved money during 2000-2004

Answer: D