Problem $4($Recovery Control$)[20$ Points$]$

The following is a sequence of undo$-$log records written by two transactions T and U:

; ; ; ; ; ; ; ;

Describe the action of the recovery manager, including the changes to both disk and the log if there is a crash and the

last log record to appear on disk is:

$($a$)<$ Start U$>$

$($b$)$

$($c$)$

$($d$)$