$4)(15$ points$)$ Consider the following schedules on three transactions $T1,T2$ and $T3.$

First determine whether each schedule is a serial, conflict serializable or

non$-$serializable schedule. Then determine whether each schedule is

cascadeless, recoverable, or nonrecoverable. Remember to answer all that

apply. Briefly explain your answers. $($Note: r$1($X$)$ means transaction T$1$ reads

data X$.$ w$2($Z$)$ means transaction T$2$ writes to data Z$.$ c$3$ stands for transaction

T$3$ commit.$)$

$4$a$)$ r$2($Z$)$; r$2($Y$)$; w$2($Z$)$; w$2($Y$)$; c$2$; r$1($X$)$; r$1($Y$)$; w$1($Y$)$; c$1$; r$3($X$)$; w$3($X$)$; r$3($Z$)$; w$3($Z$)$; c$3$;

$4$b$)$ r$1($X$)$; r$3($X$)$; r$2($Z$)$; r$2($Y$)$; w$2($Z$)$; w$3($X$)$; r$3($Z$)$; w$2($Y$)$; r$1($Y$)$; c$2$; w$1($Y$)$; c$1$; w$3($Z$)$; c$3$;

$4$c$)$ r$3($X$)$; r$2($Z$)$; w$3($X$)$; r$1($X$)$; r$2($Y$)$; w$2($Z$)$; r$3($Z$)$; w$3($Z$)$; c$3$; r$1($Y$)$; w$1($Y$)$; c$1$; w$2($Y$)$; c$2$;