Consider the following schedule S$2$:

S$2$: R$1($A$)$; R$2($D$)$; R$1($C$)$; W$1($C$)$; W$2($A$)$; Commit$2$; R$1($B$)$; Commit$1$;

Extend S$2$ with lock and unlock actions such that it adheres to the S$2$PL $($i$.$e$.$ Strict $2$PL$)$

protocol and is deadlock$-$free. If this is impossible, explain why.

Hint: Create a table with one column per transaction and one row per action $($including

transactions$$ actions and lock and unlock actions$).$