Final answer:
The availability of a trained labor pool is an example of external economies of scale, referring specifically to industry-wide benefits from a skilled workforce.
Step-by-step explanation:
The availability of a pool of trained labor, as a form of external economies of scale, refers to the benefits gained by an industry as a whole through access to a skilled and trained workforce. This advantage is not about the cost savings from producing a larger volume of goods or from more efficient production processes within an individual organization, but rather the cost benefits that accrue to firms in an industry thanks to a shared pool of skilled labor.
These external economies of scale can result in an industry cluster where businesses benefit from the availability of a large, versatile labor pool with specialized knowledge and skills, thus potentially lowering their costs related to training and recruitment, and enhancing overall productivity.