Final answer:
The first valid host on the subnetwork that the given node belongs to is 172.31.226.177.
Step-by-step explanation:
To determine the first valid host on the subnetwork, we need to use the given IP address and subnet mask. The given IP address is 172.31.226.184 and the subnet mask is 255.255.255.240.
By applying the bitwise AND operation between the IP address and the subnet mask, we can determine the network address. Performing this operation, we get 172.31.226.176 as the network address. The first valid host on this subnetwork would be the network address plus 1, which gives us 172.31.226.177.
Therefore, the correct answer is 172.31.226.177.