An argument proposes: "To reduce traffic congestion, our city should encourage more residents to use public transportation by offering free bus passes. This will lead to fewer cars on the road and faster commutes for everyone."

The correct answer to the question "An argument proposes: "To reduce traffic congestion, our city should encourage more residents to use public transportation by offering free bus passes. This will lead to fewer cars on the road and faster commutes for everyone."" is Option A: Data on current public transportation usage and routes..

The other options — B) The average cost of maintaining city roads., C) A comparison of fuel prices in the city versus surrounding areas., D) The number of taxis operating in the city. — are incorrect for this GMAT Exam Prep question. As explained above: To assess if free passes will reduce congestion, it's crucial to know current public transport ridership, existing routes' coverage, and how many people are likely to switch from cars.