a.The matrix need is:

Need

________

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.Safe with the order of P0-P2-P1-P3-P4

c.the request can be granted immediately

because the request for P1 is (0,4,2,0),which is <= available(1,5,2,0),so the status is true,and the new system state is also safe.