Final answer:
The most advised answer is: you should never stand on the top step of a ladder due to safety considerations, the risk of falls, and possible injury, regardless of whether the employer gives permission or not.
Step-by-step explanation:
Regarding when you are allowed to stand on the top step of a ladder, the most recommended advice based on health and safety standards is option c: you should never stand on the top step of a ladder. This is due to safety reasons as the top step does not provide sufficient support and can lead to accidents like falls. Even if there's something unreachable, alternative means should be found instead of standing on the top step. Employer permission does not override safety regulations and reasonable precautionary measures.
Learn more about Ladder Safety