What should be checked with the electrical line in a pre-trip inspection?

During a pre-trip inspection, checking the electrical line is crucial for the safe operation of the vehicle. The correct response emphasizes that the electrical line should have slack to ensure flexibility. This is important because sufficient slack allows the line to move with the vehicle without putting undue strain on the connections, which can lead to wear, damage, or disconnection during operation.

Maintaining flexibility in the electrical line reduces the risk of breakage from stress caused by the vehicle's movement, especially during turns or uneven terrain. Furthermore, an electrical line that is too tight may pull on connectors and lead to malfunctions, posing safety hazards.

The other choices suggest practices that could lead to operational issues. For instance, unplugging the electrical line for maintenance checks is not typically necessary and should be done according to specific maintenance protocols rather than as a standard check. A loose electrical line could cause disconnections and may not be safe, while allowing a worn-out line to function is counterproductive and could lead to electrical failures or safety incidents.