Final answer:
Option c, which describes greeting a customer within 15 seconds of entering the store, represents a measurable performance standard for a clerk at a movie rental store.
Step-by-step explanation:
The question pertaining to the performance standard for a clerk at a movie rental store essentially seeks to determine which of the listed actions is a metric used to evaluate a clerk's effectiveness on the job. While actions such as stocking coolers, operating the cash register, and filing returned DVDs are typical duties, the performance standard is typically a measurable and observable level of service or conduct that employees are expected to achieve. In this case, option c, which says "Greets customer within 15 seconds of entering store", represents a specific performance standard. It sets a clear and quantifiable expectation for how quickly a clerk must engage with a customer, impacting the customer's experience and satisfaction.