Quote Originally Posted by DeusExMachina View Post
145.36.4.0/22 is the next available subnet if 145.36.0.0/22 is used. Maybe that's what he meant by available.

Because I doubt a professor would call a basic subnetting question "very difficult". It is likely purposefully confusing.
145.36.4.0/22 is not a valid CIDR designation....145.36.4.0 lives under 145.36.0.0/21