Final answer:
The shift operator at a 500 boiler horsepower plant, under the supervision of a chief engineer, would most likely require a second-class engineer's license. This level of licensure ensures appropriate responsibility and expertise without overqualifying the position, which is one step below the chief engineer's role.
Step-by-step explanation:
The question pertains to the level of licensure required for a shift operator in a plant where the chief engineer is in charge of a plant of 500 boiler horsepower. In settings where boilers and heavy machinery are involved, specific licensure is mandated to ensure the safety, efficiency, and compliance of the operations. To provide an accurate response, one would typically refer to state or regional regulations that govern the operation of such equipment. However, as a general rule, there are different classes of licenses for engineers operating in industrial settings.
Options such as chief engineer, first-class engineer, second-class engineer, and special engineer's license refer to varying levels of responsibility and expertise. The chief engineer is typically the highest-ranking engineer responsible for the entirety of the plant operations and not the shift operator's position, which tends to be a more immediate operational role. Considering a plant that has a chief engineer with a 500 boiler horsepower plant, the shift operator would not necessarily require a chief engineer's license. Rather, they would need a level of certification that qualifies them to handle day-to-day operations under the chief engineer's supervision.
Given the context, and without specific regional regulations provided, the most appropriate approach would be to assume the license required is one step below the chief engineer for the shift operator position. If we must choose any one option in the final part clearly, and given that 'chief engineer' is the top tier, we would mention the correct option in the final answer as a second-class engineer (Option C), presuming a progression from chief to first to second. This choice is a moderately safe assumption when lacking specific regulatory detail but still ensures a high level of expertise and responsibility suitable for a 500-boiler horsepower plant.