1. Assume a file system with 3 users: Alice, Bob, and Charlie. There are three files: file1, file2, and file3, with the following access rights: Alice can access file1 (read, write), file2 (read), and file3 (write) Bob can access file2 (read), and file3 (read, write) Charlie can access file3 (read) (a) Write the access control matrix for the system given the above subjects and objects and access rights. (20 points) b) Write the access control lists for the files given the above subjects and objects and access rights. (20 points