For those who didn't get why if not serialzable then not 2pl.?
we must know that if schedule is 2pl(P) then it is serialzable(Q) too
So,P->Q which is equivalent to its contrapositive parts i.e ~Q->~P
which states that if not serialzable then not 2pl.
In Schedule given we can easily prove that it is not serialzable and hence not occur in 2pl.