What action should be taken to ensure visibility if a person is trapped in darkness?

Using a flashlight is the best action to ensure visibility if a person is trapped in darkness. A flashlight provides a focused beam of light that can penetrate the surrounding darkness, making it easier for rescuers to locate the person. It also allows the trapped individual to signal for assistance, increasing the chances of a successful rescue.

In situations of low visibility, the effectiveness of using a flashlight outweighs other methods. Unlike a candle, which has limited light output and poses a fire hazard, a flashlight is designed specifically for illuminating dark areas and is generally safer. While holding a reflective surface might catch some light, it does not produce light and would be ineffective in complete darkness. Waving a brightly colored cloth could visually signal for help, but it relies on the presence of light to be seen. In contrast, activating a flashlight directly addresses the issue of darkness by generating light that can both guide rescuers and provide visibility for the individual in need of help.