In the scenario described, the engineer needs to configure DHCP Option 43 to provide the management IP address of the WLC in a format that the access points can understand. The correct configuration for Option 43 includes the IP address of the WLC in hexadecimal format. The management IP address of the WLC is 172.16.50.5, which translates to AC10.3205 in hexadecimal notation. The prefix F104 indicates that it is an IPv4 address and specifies its length (in this case, four bytes or one word). Therefore, configuring option 43 with Hex F104.AC10.3205 will resolve the issue by directing access points to find and register with the WLC at IP address 172.16.50.5.