What additional safety measure is important when securing cargo?

Answer: C — Ensuring cargo does not exceed vehicle's weight limit

When securing cargo, it is crucial to ensure that the cargo does not exceed the vehicle's weight limit. Adhering to this limit is essential for maintaining vehicle stability, control, and overall road safety. Overloading a vehicle can lead to poor handling and increase the risk of accidents, as excessive weight may cause brakes to fail or tires to blow out. Moreover, it can result in serious legal and financial repercussions, such as fines or damage to the vehicle. In contrast, while having adequate visibility through mirrors and using appropriate tie-downs are important for safe vehicle operation and secure cargo, they do not directly address the overarching concern of weight limits. Leaving space between tied down items is less pertinent as it could actually lead to shifting cargo during transit if not properly managed. Thus, understanding and respecting the vehicle's weight limitations is the fundamental safety measure that should always be prioritized when securing cargo.