Question

when should you exercise extreme caution around power lines? select the best option. when a qualified person determines it to be necessary whenever you work around them when there have been accidents in similar situations recently only when you work with cranes near power lines

Explanation:

Power lines are always potentially dangerous. Even if there seems to be no immediate danger or no recent accidents in similar situations, or no specific equipment like cranes is involved, one should always be cautious. A qualified person's determination might not cover all scenarios, and waiting for an accident precedent is not a safe approach. Working around power lines inherently carries risks that require constant caution.

Answer:

Whenever you work around them