In which one of the following page replacement policies, Belady’s anomaly may occur?

Consider a system with 4 types of resources R1 (3 units), R2 (2 units), R3 (3 units), R4 (2 units). A non-preemptive resource allocation policy is used. At any given instance, a request is not entertained if it cannot be completely satisfied. Three processes P1, P2, P3 request the sources as follows if executed independently. Which one of the following statements is TRUE if all three processes run concurrently starting at time t = 0?

A CPU generally handles an interrupt by executing an interrupt service routine

In the following process state transition diagram for a uniprocessor system, assume that there are always some processes in the ready state:

Now consider the following statements:
$$1.\,\,\,$$ If a process makes a transition $$D,$$ it would result in another process making transition $$A$$ immediately.
$$2.\,\,\,$$ $$A$$ process $${P_2}$$ in blocked state can make transition $$E$$ while another process $${P_1}$$ is in running state.
$$3.\,\,\,$$ The $$OS$$ uses preemptive scheduling.
$$4.\,\,\,$$ The $$OS$$ uses non-preemptive scheduling. Which of the above statements are TRUE?