Consider three processes $P_1,P_2,P_3$ all arriving at time 0, having same priority 0 initially and they arrive in order $P_1,P_2,P_3$

Now my ready queue looks like

After $T$ time units,

Waiting times of P1,P2,P3 are 0,T,T respectively. Clearly, since priority is assigned proportional to the waiting time, P2 and P3 would be given priority over P1 and P1 is sure to get preempted.

Ready queue says P2 will be executed next. Cool!

So, P1 put at the tail of the ready queue and the ready queue is now

After another $T$ units of time

Waiting times of P1,P2,P3=T,T,2T

Clearly, P2 will be preempted now and P3 would get a chance

Ready queue becomes

After another T units of time

Waiting times of P1,P2,P3=2T,2T,2T. All have same priorities, so T3 can be allowed to execute next.

After another T units of time

Waiting times of P1,P2,P3=3T,3T,2T. Now surely P3 would be preempted and now ready queue becomes

P1 executed next for T units of time.

Waiting times of P1,P2,P3=3T,4T,3T

P2 would get chance now and the ready queue will be

Clearly this scheme is not one of SRTF or SJF or FCFS because otherwise after T time units, in case of SRTF atleast one job would have been computed in it's entirety at some point of time and same with the SJF, and with FCFS, arrival time would have mattered and not priority based on waiting time!!

So basically this algorithm is ensuring that the waiting time of each job is bounded by some constant in terms of time quanta T units and ensure every job gets a chance.That is the job of RR scheduling.!!

**Answer-(B)**