Which of the following points to a reduction in the average cost of a unit produced as production output increases?

The best operating level pertains to the optimal capacity at which a firm can produce goods most efficiently, but it does not directly imply a reduction in average costs with increased production. It is more about maximizing efficiency at a specific level of output rather than the overall cost dynamics related to scaling production.

Diseconomies of scale occur when a company's production costs per unit increase as production volume rises. This situation often arises when a company becomes too large and complex, leading to inefficiencies. Thus, this option directly contradicts the notion of costs decreasing with increased output.

Focused factories refer to production facilities that specialize in a limited range of products to improve efficiency and quality. While this strategy can enhance productivity and lower costs for specific products, it doesn't inherently point to a reduction in average costs due to increased overall production across a range of products.