7. 6 points each Express these system specifications using the propositions p: "The user enters a valid password," : "Access is granted," and r: "The user has paid the subscription fee" and logical connectives (including negations). a) "Access is granted whenever the user has paid the subscription fee and enters a valid password." b) "Access is denied if the user has not paid the subscription fee." c) "If the user has not entered a valid password but has paid the subscription fee, then access is granted