You need to filter traffic for the 192.168.1.0/25 network. Which wildcard mask would you use?

A wildcard mask is the opposite of a network mask. The easy way to calculate a wildcard mask is to take 255 minus the subnet mask octet. For /25 (255.255.255.128), the wildcard mask is 0.0.0.127. The network mask 255.255.255.128 would be used for subnet configuration, not ACLs.