What type of equipment is vital for a lifeguard when making a rescue?

The vital piece of equipment for a lifeguard when making a rescue is the rescue tube. A rescue tube is designed to provide flotation assistance to an individual in distress and can also serve as a tool for the lifeguard to safely reach and secure the person requiring help. This equipment is specifically constructed to support both the lifeguard and the victim, ensuring that both can remain afloat during the rescue process.

In contrast, while items such as a beach ball, whistle, and sunblock cream have their uses around a pool or beach environment, they do not aid in the actual rescue process. A beach ball is a recreational item with no functional role in lifesaving. While a whistle can be important for signaling and communication, it cannot provide physical support or flotation to a drowning person. Sunblock cream is essential for skin protection from sun exposure but does not assist in any emergency situations related to water rescues. Thus, the rescue tube is the only equipment among the options that is specifically designed for the crucial purpose of saving lives in aquatic environments.