For Part C:
Mutual Exclusion is violated. Consider the following sequence of execution after exchanging and see for yourself:
S1,Q1,Q2,Q3,S2,S3,Q4,Q5,Q6,S4,Q7,Q1,Q2,Q3,Q4,Q5,S5,....
As both processes are using the resources simultaneously in Q5 and S5, Mutual exclusion is violated.