Consider the following algorithm based on question $(2).$ If exp is initially $15$ how many recursive calls will be made?

int power $($int exp, int x$)\{$

if $($exp$==0)$ return $1$;

else $\{$

int temp$=????$

if $($exp$\%2==0)$ return temp;

else return temp$*$x;

$\}$

$\}$

Question $3$Select one:

a$.$

$2$

b$.$

$3$

c$.$

$5$

d$.$

$4$