Final answer:
Method 3: Stateful DHCPv6 is the dynamic addressing method for GUAs where devices solely rely on a DHCPv6 server for their addressing information.
Step-by-step explanation:
The dynamic addressing method for GUAs where devices rely solely on a DHCPv6 server for their addressing information is Method 3: Stateful DHCPv6. In this method, the DHCPv6 server provides both the IPv6 address and other configuration parameters to the device. This method is commonly used in enterprise networks where centralized management is preferred.