$[2]$ Which of the following is true of the two$-$phase locking protocol?

$($a$)$ every transaction goes through a growing and then a shrinking phase

$($b$)$ a transaction never releases a lock until it has reached a stage where no new locks will be needed

$($c$)$ once a transaction releases a lock, it can never acquire any new locks

$($d$)$ all of the above