Which command would configure an ACL to block traffic coming from 192.168.1.0/24?

The command ip access-list 20 192.168.1.0 0.0.0.255 will configure an access list of 20, which is a standard access list. The source address of 192.168.1.0 is wildcard masked with 0.0.0.255. The other commands are incorrect: 100 is an extended ACL number, /24 notation is not valid in ACL syntax, and 255.255.255.0 is a subnet mask not a wildcard mask.