Consider the following concurrency control protocols: $2$PL$,$ Strict $2$PL$,$ Conservative $2$PL$,$ Timestamp without the Thomas Write Rule, Times tamp with the Thomas Write Rule, and Multiversion.

a$.$ For each of the following schedules, state which of these protocols allows it$$that is$,$ allows the actions to occur in exactly the order shown.

b$.$ Give reasons for at least two $"$No$"$ answers if they were found for each concurrency technique.

$($Assume that the timestamp of transaction Ti is $\text{'}$i$.)$

$1.$ R$1($X$),$ R$2($X$),$ W$1($X$),$ W$2($X$)$

$2.$ W$1($X$),$ R$2($Y$),$ R$1($Y$),$ R$2($X$)$

$3.$ R$1($X$),$ R$1($Y$),$ W$1($X$),$R$2($Y$),$ W$3($Y$),$ W$1($X$),$ R$2($Y$)$

$4.$ R$1($X$),$ W$2($X$),$ W$1($X$),$ T$2$:Abort, T$1$:Commit

$5.$ R$1($X$),$ R$2($Y$),$ W$3($X$),$ R$2($X$),$ R$1($Y$)$

$6.$ R$1($X$),$ W$2($X$),$ W$1($X$),$ T$2$:Commit, T$1$:Commit

$7.$ W$1($X$),$ R$2($X$),$ W$1($X$),$ T$2$:Commit, T$1$:Commit

$8.$ W$1($X$),$ R$2($X$),$ W$1($X$),$ T$2$:Commit, T$1$:Abort

$9.$ W$1($X$),$ R$2($X$),$ W$1($X$),$ T$2$:Abort, T$1$:Commit

$10.$ R$2($X$),$ W$3($X$),$ T$3$:Commit, W$1($Y$),$ T$1$:Commit, R$2($Y$),$ W$2($Z$),$ T$2$:Commit

$11.$ R$1($X$),$ W$2($X$),$ T$2$:Commit, W$1($X$),$ T$1$:Commit, R$3($X$),$ T$3$:Commit

$12.$ R$1($X$),$ W$2($X$),$ W$1($X$),$ R$3($X$),$ T$1$:Commit, T$2$:Commit, T$3$:Commit

Answer $($ a$)$ by filling the table below:

$2$PL S$-2$PL C$-2$PL TSwo$/$Twr TSw$/$Twr Multiv

$1($example$)$ No No No No No No

$2$

$3$

$4$

$5$

$6$

$7$

$8$

$9$

$10$

$11$

$12$

Note the following abbreviations. S$-2$PL: Strict $2$PL; C$-2$PL: Conservative $2$PL; TS wo$/$ Twr: Timestamp without Thomas Write Rule; TSw$/$ Twr : Timestamp withThomas Write Rule; MultiversionTSo :Multiv.