What must be checked regarding the fuel tank cap during inspection?

The requirement that the fuel tank cap must be locked while driving is crucial for safety and efficiency during vehicle operation. A secure fuel tank cap prevents fuel from spilling out while the vehicle is in motion, which can reduce the risk of accidents and environmental contamination. Additionally, a locked fuel cap helps to maintain the correct pressure within the fuel system and can deter fuel theft.

Other options present alternatives that do not meet safety standards. For instance, a loose cap could lead to fuel leakage, while a cracked cap would compromise the integrity of the fuel system. The cap's color is irrelevant to its functionality and safety. Thus, ensuring that the fuel tank cap is locked is a vital aspect of the pre-trip inspection process.