1. (15%) Consider a computer system with three users: Alice, Bob, and Cyndy. Alice owns the file a, and Bob and Cyndy can read it. Bob owns the file b, and Cyndy can read and write the file b, but Alice can only read it. Cyndy owns the file c, but neither Alice and Bob can read or write it. If a user owns a file, he/she can also execute the file.(a) Create the ACM (access control matrix) of the system.(b) Show the ACL of the ACM and the CL of the ACM.(c) Cyndy gives Alice permission to read c, and Alice removes Bob's ability to read a. Show the ACM after these changes.