Four processes $-$ A$,$ B$,$ C and D $-$ are ready to execute, having arrived in that order.

They require different numbers of quanta to complete and request different priorities $(1$

is lowest, $4$ is highest$)$:

Process A requires $2$ quanta, requested priority $1$

Process $B$ requires $4$ quanta, requested priority $4$

Process $C$ requires $5$ quanta, requested priority $2$

Process $D$ requires $3$ quanta, requested priority $3.$

What is the pattern of execution under the following scheduling strategies:

ii$.$ first$-$in$,$ first$-$out

iii. round$-$robin

iv$.$ priority.

Give your answer by showing which process executes at each quantum until all

processes complete, for example: A C C B B $...$

v$.$ How many quanta are required for each process and $D$ to terminate

under round$-$robin scheduling?