Consider the following set of processes that need to be scheduled on a single CPU. All the times are given in milliseconds.

Process Name	Arrival Time	Execution Time
A	0	6
B	3	2
C	5	4
D	7	6
E	10	3

Using the shortest remaining time first scheduling algorithm, the average process turnaround (in milliseconds) is ____

Using SRTF scheduling:

$A: 0 \to 3$

$B: 3 \to 5$

$A: 5 \to 8$

$C: 8 \to 12$

$E: 12 \to 15$

$D: 15 \to 21$

Completion times:

$A=8,\ B=5,\ C=12,\ D=21,\ E=15$

Turnaround time $=$ Completion time $-$ Arrival time

$A=8-0=8$

$B=5-3=2$

$C=12-5=7$

$D=21-7=14$

$E=15-10=5$

Average turnaround time:

$=\frac{8+2+7+14+5}{5}$

$=\frac{36}{5}$

$=7.2$

Correct option is:

$\boxed{(a)\ 7.2}$