What type of economies involves specialization through employing specialists and using specialized machinery?

The correct choice highlights the concept of technical economies, which occurs when a firm becomes more efficient due to the use of specialized machinery and the employment of specialists. In this context, technical economies refer to the advantages gained from adopting advanced technology and techniques that allow for increased production efficiency.

By using specialized machinery, firms can produce goods at a lower cost per unit. Additionally, employing specialists means that tasks are completed by individuals with expertise, leading to higher productivity and efficiency in production processes. This specialization allows for better use of resources and improved overall output, facilitating the ability of firms to benefit from large-scale production.

In contrast, economies of scale focus more on the cost advantages gained as production increases overall scale rather than the technical aspects. Risk-bearing economies relate to the ability to spread risk across a larger volume of production and costs, while diminishing returns to scale refers to a situation where increasing production eventually leads to a less proportional increase in output. Therefore, the emphasis on specialization through both machinery and human expertise in the correct answer distinctly aligns with the principles of technical economies.