$[20$pts$]($Exercise $17\mathrm{.}2)$ Consider the following classes of schedules: serializable, conflict$-$serializable, recover$-$

able, avoids$-$cascading$-$aborts, and strict. For each of the following schedules, state which of the preceding

classes it belongs to$.$ If you cannot decide whether a schedule belongs in a certain class based on the listed

actions, explain briefly.

The actions are listed in the order they are scheduled and prefixed with the transaction name. If a commit or abort

is not shown, the schedule is incomplete; assume that abort or commit must follow all the listed actions.

$($a$)T_1$:$R(x),T_2$:$R(Y),T_3$:$W(x),T_2$:$R(x),T_1$:$R(Y)$

$($b$)T_1$:$R(x),T_1$:$R(Y),T_1$:$W(x),T_2$:$R(Y),T_3$:$W(Y),T_1$:$W(x),T_2$:$R(Y)$

$($c$)T_1$:$W(x),T_2$:$R(x),T_1$:$W(x),T_2$: Abort, $T_1$: Commit

$($d$)T_1$:$R(x),T_2$:$W(x),T_2$: Commit, $T_1$:$W(x),T_1$: Commit, $T_3$:$R(x),T_3$: Commit