After a systems failure, the undo$-$redo recovery $log$ has the following entries:

An entry $($:$T,x,u,v$:$)$ means that transaction $T$ has updated the value of $x$ from $u($the old value$)$ to $v($the

new value$).$ The redo phase proceeds the undo phase during the recovery.

a$)$ Which are the transactions whose actions the recovery manager needs to redo?

b$)$ Which are the transactions whose actions the recovery manager needs to undo?

c$)$ Indicate the actions of the recovery manager on all the elements, separately during the Redo and the

Undo phase.