Which of the following individuals must not operate a stacker?

The primary reason that child labor must not operate a stacker is due to the legal restrictions and safety considerations associated with minors. In many jurisdictions, there are strict laws governing the types of work that individuals under a certain age can perform, particularly in environments that involve heavy machinery or equipment like stackers.

Operating a stacker requires a level of physical strength, training, and mental maturity that young children do not possess. Safety is paramount in the operation of such machinery; therefore, allowing children to handle stackers poses significant risks not only to themselves but also to those around them.

While young and inexperienced workers may need additional training or supervision, they are not outright prohibited from operating machinery if they are of legal age and have received appropriate training. Disabled individuals might also operate forklifts or stackers if they can do so safely with necessary accommodations. Thus, the emphasis on child labor prohibits their involvement due to both legal frameworks and the imperative of ensuring workplace safety.