Despite a significant increase in the average fuel efficiency of new cars sold this year compared to last year, the total amount of gasoline consumed by all cars on the road has slightly increased.

The correct answer to the question "Despite a significant increase in the average fuel efficiency of new cars sold this year compared to last year, the total amount of gasoline consumed by all cars on the road has slightly increased." is Option A: The price of gasoline decreased steadily throughout the year, encouraging more driving..

The other options — B) Car manufacturers focused on improving fuel efficiency for larger, less efficient vehicles., C) Public transportation ridership decreased as more people opted for personal vehicles., D) Older, less fuel-efficient cars remained on the road in greater numbers than anticipated. — are incorrect for this GMAT Exam Prep question. As explained above: If gasoline prices dropped, people might drive more miles overall. This increased driving volume could offset the gains from improved fuel efficiency, leading to higher total gasoline consumption.