正解:D
The script shown in the exhibit uses the ncclient library in Python, which is a client for NETCONF (Network Configuration Protocol). The manager.connect method is used to establish a session with a network device using NETCONF over SSH. The script then retrieves the running configuration of the device using the get_config method with 'source': 'running', specifying that it wants to retrieve the running configuration data. Finally, it writes this data into an XML file named after the host variable. This process is typically used for network automation tasks such as backing up configurations or programmatically retrieving information from network devices.