Which method can effectively alert a buddy during a dive?

Making eye contact is an effective method to alert a buddy during a dive because it establishes direct communication, ensuring that both divers are aware of each other's presence and intentions. In an underwater environment, it can be challenging to communicate verbally or through gestures due to potential noise and visibility issues. By making eye contact, you can quickly confirm that your buddy is attentive and ready to respond to whatever situation may have arisen.

This method also adds a layer of reassurance, as it allows both divers to gauge each other's comfort level and readiness. When a diver notices that eye contact has been established, it helps in fostering a sense of teamwork and coordination. In contrast, while the other methods listed are valid means of communication, they may not be as immediate or effective under water, where visibility and sound communication are often compromised.