Final answer:
Auto-discovery-sender enabled in a VPN setup enables automatic sender discovery without the need for manual configuration.
Step-by-step explanation:
In a VPN setup, the term auto-discovery-sender enabled refers to a feature that allows the automatic discovery of the sender's IP address. It enables the VPN hubs to automatically identify and establish communication with the sender without the need for manual configuration. This feature is particularly useful in dynamic network environments where IP addresses may change frequently.
For example, let's say you have a VPN setup with multiple hubs and a sender wants to communicate with a specific hub. With auto-discovery-sender enabled, the sender can simply initiate the communication, and the VPN hubs will automatically identify and connect with the sender's IP address, eliminating the need for manual configuration.
Therefore, option a) Enables automatic sender discovery is the correct answer.