Consider the $4$ processes below, where A$,$ B$,$ C$,$ D are arbitrary computations:

process $1$:process $2$:process $3$:process $4$;P$($s$1)$;P$($s$2)$;P$($s$1)$;P$($s$1)$;A;B;C;D;V$($s$2)$;V$($s$1)$;V$($s$1)$;V$($s$2)$;

The initial semaphore values are: s$1=0,$ s$2=1$

Assuming that all processes start concurrently, what are the possible sequences of executions of A$,$ B$,$ C$,$ D after all$$ processes stop executing?

Sn$+1=$Tn$+(1$$)$Sn

For each combination of values, determine what the prediction is based on$.$

TnSnSn$+1$Prediction is

based on:$242[$ Select $]["$only the last observation", "only the last prediction", "both the last observation and the last prediciton$$ last"$]244[$ Select $]["$only the last observation", "only the last prediction", "both the last observation and the last prediciton$$ last"$]243[$ Select $]["$only the last observation", "only the last prediction", "both the last observation and the last prediciton$$ last"$]$