What is the expected response time for answering all calls?

The expectation of responding to calls "promptly" indicates that there is an emphasis on timely communication without specifying an exact timeframe. This choice implies a commitment to addressing calls in a manner that demonstrates urgency and efficiency, aligning with the standards of customer service typically expected in transit operations.

Promptness suggests a prioritization of public safety, service quality, and operational effectiveness, where responders are trained to engage with inquiries or issues as quickly as possible while still ensuring thoroughness in their responses.

The other options specify either an exact timeframe or an inappropriate suggestion for responding to calls. For example, responding "immediately" might not always be feasible depending on the situation or call volume, while "within one hour" is more restrictive than what is generally accepted. Responding "at the end of the shift" could result in unacceptable delays, showing a lack of responsiveness to pressing matters throughout the course of the day. Thus, "promptly" remains the most suitable expectation for response time.