Final answer:
In challenge-and-reply authentication, the time limit for the calling station to authenticate varies and is set by system administrators. It commonly ranges from a few seconds to a minute, balancing security needs with practical considerations for network and user response times.
Step-by-step explanation:
In challenge-and-reply authentication, the time frame for the calling station to authenticate varies depending on the specific system or network configuration. Generally, there is not a standardized duration for the response time as it is defined by the administrators of the system in question. However, it is common for the system to enforce a reasonable time limit to ensure security and efficiency. This limit might range from a few seconds to a minute, but it's essential that the time allowed is brief enough to prevent potential attackers from exploiting the authentication process, while also being long enough to account for network delays and user input time.