1. You are asked to develop a system for managing maintenance of computers. Your subjects are CompanyOne, CompanyTwo, CompanyThree, and CompanyFour, and Bob. The system has computers1, 2, and 3 as objects. The rights are Use, Priority, and Shutdown (a) Draw the access control matrix (as in the Harrison-Ruzzo-Ullman model) for the above system, giving CompanyOne Priority on computer land Use of computers 1 and 3, CompanyTwo Priority and Use on computer2, CompanyThree Use of computer 1, and CompanyFour Use of computer 2 and 3. (7pt) (b) If a subject has Priority on a computer, that computer cannot be shut down without his permission. Assuming that at most one subject is given Priority on any computer; write a command that allows a subject to give another subject the right to Shutdown a computer. (6pt)