Which factor contributes to better fuel economy in a car?

Answer: C — Regular maintenance

Regular maintenance plays a vital role in ensuring that a vehicle operates efficiently, which directly contributes to better fuel economy. When a car is well-maintained, it means that all of its systems are functioning as intended. This includes timely oil changes, air filter replacements, and proper lubrication of moving parts. Each of these aspects helps the engine to run smoothly, reducing fuel consumption and enhancing overall efficiency. For example, an engine with clean oil and filters can breathe better and operate at optimal performance levels, which translates into less fuel needed for the same power output. Additionally, regular maintenance checks can identify and fix issues such as spark plug problems or fuel injector malfunctions that could otherwise lead to increased fuel usage. The other factors, such as a heavy load, dirty air filters, and improper tire pressure, are detrimental to fuel economy. A heavy load requires more power from the engine, leading to higher fuel consumption. Dirty air filters restrict airflow, harming engine performance and efficiency. Lastly, improper tire pressure can result in increased rolling resistance, making the engine work harder and further decreasing fuel economy.