Which OSPF wildcard mask corresponds with the network 128.107.0.0 255.255.252.0?

To determine the correct OSPF wildcard mask for the network 128.107.0.0 with a subnet mask of 255.255.252.0, it is essential to understand how wildcard masks are derived from subnet masks.

A wildcard mask is obtained by subtracting each octet of the subnet mask from 255. This calculation highlights the bits that are of interest for OSPF's routing decision process. Given the subnet mask 255.255.252.0, we can break it down:

1. The first octet: 255 - 255 = 0

2. The second octet: 255 - 255 = 0

3. The third octet: 255 - 252 = 3

4. The fourth octet: 255 - 0 = 255

Putting these calculations together, the wildcard mask comes out to be 0.0.3.255. This means that OSPF will match the first two octets exactly (the 0s indicate that they must match), while it allows for any value in the last two octets (the 3 in the third octet indicates that the last two bits can vary within that octet, which corresponds