Could you please give the specific reason and explanations? Not just the right answer, thanks a lot.

Using the Banker's algorithm given the following resources held by processes and available resources does the request by PO of (1,2,1,1) result in a safe state? Allocation Max Available ABCD ABCD ABCD PO 2001 4212 4532 P1 3121 5252 P2 2103 2316 P3 1312 1424 P4 1432 3665 Yes and PO, P1, P2, P3 and P4 is a safe sequence O Yes but we cannot find a safe sequence