Suppose burst time of A is x, its mention A has already run for 6 unit of time, so Remaining Burst time for A is x-6, now it get preempted by B
Now Suppose Burst time of B is y, its mention B has already run for 2 unit of times before getting preempted by C, so remaining burst time for B is y-2.
Now C run for 4 unit of time.
Now given B is preempted by C, so C has shortest BT as compare to B, i.e minimum value of y-2 must be 5, then only it get preempted by C
Therefore y-2 = 5, so y = 7.
Similarly x-6 = 8, and x = 14
Therefore burst time of A and B is 14 and 7, which is not matched by any option, so none of the above.