Why is checking fluid levels before an inspection advisable?

Checking fluid levels before a vehicle inspection is advisable primarily to avoid potential issues that could affect the vehicle's performance and ability to pass the inspection. Fluid levels—such as engine oil, coolant, brake fluid, transmission fluid, and power steering fluid—are critical for the proper functioning of a vehicle. Low or contaminated fluids can lead to mechanical failures or safety issues that could cause the vehicle to fail the inspection.

For instance, low brake fluid can affect braking performance, while insufficient engine oil can lead to engine damage. Inspectors look for signs of maintenance and proper function, and having adequate fluid levels and cleanliness demonstrates that the vehicle has been well cared for, which is beneficial for passing the inspection.

The other options do not directly relate to the mechanics and safety aspects that are considered during a vehicle inspection. Improving a vehicle's color or appearance does not affect its functionality, while impressing an inspector does not guarantee that the vehicle meets safety and operational standards. Hence, the focus on fluid levels is about ensuring the vehicle is in suitable condition to pass inspection.