a.      A B C D

p0 0 0 0 0

P1 0 7 5 0

P2 1 0 0 2

P3 0 0 2 0

P4 0 6 4 2

b.Yes. The system is in safe. Because for the sequence of p0, p3, p1, p2, p4. The all process can be finish. At first, we can conclude that p0 is finish, and then, p0 can release all the resource, the available turn to be (1 5 3 2), which is larger than p3 Need(0 0 2 0).After p3 finished, the available turn to be(1 11 8 4) and so on. At last all the process is finish. So it is in safe.

c.Yes. Because t