How frequently should the brake system on a trailer be serviced?

The correct choice emphasizes the significance of adhering to the manufacturer's recommendations for servicing the brake system on a trailer, which typically falls within the range of 10,000 to 12,000 miles. This is crucial because manufacturers design brake systems to operate optimally within specific maintenance intervals. Regular servicing at these intervals helps to ensure that the brakes remain in good working condition, which is vital for safety and performance. Moreover, factors such as braking conditions, load weights, and environmental factors can affect brake wear, making adherence to the manufacturer's guidance an important practice for maintaining the integrity of the braking system and ensuring safe operation.

While there are other suggestions for service intervals, they may not account for the specific conditions and recommendations set by the manufacturer, which is why following option B is the best practice for maintaining trailer brake systems.