Consider the pattern of red and green packet arrivals to a router's output port queue, shown below. Suppose each packet takes one time slot to be transmitted, and can only

begin transmission at the beginning of a time slot after its arrival. Indicate the sequence of departing packet numbers $($at $t=1,2,3,4,5,7,8$ under round robin scheduling,

where red starts a round if there are both red and green packets ready to transmit after an empty slot.

Which of the following represents a $7$ ordered digits of the departing packets? $($each digit corresponds to the packet number of a departing packet$).$

arrival

packet i

servic

departure

$1432567$

$1243567$

$1324567$

$1423567$