4. (6 points) You are modeling a computer system which has three error flags: the COM flag is set to on when the computer is out of memory; the DEO flag is set to on when a disk error occurs; the NET flag is set to on when network connectivity is unreliable. Are the following system specifications consistent? CD CD If the computer is out of memory, then network connectivity is unreliable. No disk errors can occur when the computer is out of memory. For full credit, describe your model by associating propositional variables with each of your basic propositions and then justify why the compound propositions that result from translating the system specifications are or are not consistent