To solve this question, the user needs to know the relationship between tire pressure and mileage.

The correct answer is:

A. True

Explanation:

Maintaining the optimal tire pressure is important for the safety and longevity of the tires, as well as the fuel efficiency of the vehicle. Filling up tires with marginally more PSI than the specified limit provides better fuel efficiency, which means you can drive more miles per gallon. Overinflating the tires can lead to a rougher ride and uneven tire wear, but a slight increase in pressure can result in better mileage. Therefore, it is true that filling up tires with marginally more PSI than the specified limit increases mileage.