The iterative implementation:

int factorial$($int n$)\{$

int res $=1$;

for $($int i $=1$; i $<=$ n; i$++)\{$

res $*=$ i;

$\}$

return res;

$\}$

The recursive implementation:

int factorial$($int n$)\{$

if $($n $==0)\{$

return $1$;

$\}$ else $\{$

return n $*$ factorial$($n $-1)$;

$\}$

$\}$

Which of the following statements is correct?

Note: Negative integers are not valid inputs, so the phrase "values of n$"$ in the options below does not include these.

$($a$)$

For most values of n$,$ the iterative implementation will use at least twice as much memory as the recursive implementation

$($b$)$

For most values of n$,$ the recursive implementation will use at least twice as much memory as the iterative implementation

$($c$)$

Neither of the above