"for the IP address of GigabitEthernet0/0/0"

If we're looking for the destination subnet mask then I go for D 255.255.255.255

Destined for the IP address of GigabitEthernet0/0/0 and the IP address of G0/0/0 is 10.10.10.3/32

This test has become a grammar test instead of a technical one. The interface gi0/0/0 is directly connected and the subnet mask is /32 so the subnet must be 255.255.255.255.

The answer is C. Mask /32 is for the local address of the router. The destination subnet mask is /24.

I choose Answer B. Because the IP range of the routing path for 172.16.2.0/23 is 172.16.2.0 to 172.16.3.255 The packet destination IP 172.16.3.254 is the last available IP within this range. If the CIDR notation is /23, the subnet mask should be 255.255.254.0

* destined for the IP address of GigabitEthernet0/0/0 * Ip address of the router /32 local route

C is the good answer because the question specifies : What is the subnet mask of the destination? Local is for the local equipment, Connected is for the subnet. The good line to use in the Route Table is where you see 10.10.10.0/24. The mask is 255.255.255.0

C. 255.255.255.0 Here's why the other options are incorrect: A. 0.0.0.0: This is the default subnet mask for Class A networks, but it's not applicable here. The routing table shows specific subnet masks for each route. B. 255.255.254.0: This subnet mask could be used on a network, but it doesn't match the subnet mask in the routing table for the destination route. D. 255.255.255.255: This is a /32 subnet mask, which creates a single-host network. It's unlikely to be used for a GigabitEthernet interface connecting to another network.

It is D because "Note that the router also automatically produces a different kind of route, called a local route. The local routes define a route for the one specific IP address configured on the router interface. Each local route has a /32 prefix length, defining a host route, which defines a route just for that one IP address. For example, the last local route, for 172.16.5.1/32, defines a route that matches only the IP address of 172.16.5.1. Routers use these local routes that list their own local IP addresses to more efficiently forward packets sent to the router itself." (CCNA official Cert, p. 378)

dont confuse

Answer D - IP address of GigabitEthernet0/0/0 is a /32

C is correct because, destination is gigabitEthernet 0/0/0 and this interface is configured as /24 , which is 255.255.255.0

tricky question

D is correct

the correct answer is C after ios 15 : we have both Connected(C) route and Local(L) route. Connected route: network address with network subnet mask Local route: the interface address, so we do not need to use "sh ip int br" to check. The subnet mask is always 32 bit, since it is a host address. In this case, we are asked about the destination route subnet mask, we should check the connected(C) route.

Closed mask /32 is not the "connected" subnet (just a "local" host), in this case the interface g0/0/0 has the following configuration: (config-if)# ip add 10.10.10.3 255.255.255.0. Do not get confused, because in the "#show ip route" output, the "Local" ip address (L) will always be shown with a closed mask (255.255.255.255), but the "Connected" network (C) will show the subnet. If asked which host mask would be /32, but the subnet mask is /24.