Which of the following is not a step that must occur with every correctly working loop?

You do not set a loop control variable equal to a sentinel during each loop iteration; if you did, the loop would never repeat. However, you must initialize a loop control variable before a loop starts, compare it to a sentinel$,$ and alter it during each iteration.

a$.$ Initialize a loop control variable before the loop starts.

b$.$ Compare the loop control value to a sentinel during each iteration.

c$.$ Set the loop control value equal to a sentinel during each iteration.

d$.$ Allow the loop control variable to be altered during each iteration.