What does this function do$?$

bool foo$($string s$)$

$\{$

if $($s$.$length$()<=1)\{$ return true; $\}$

char first $=$ s$[0]$;

char last $=$ s$[$s$.$length$()-1]$;

if $($first $!=$ last$)$

$\{$

string shorter $=$ s$.$substr$(1,$ s$.$length$()-1)$;

return foo$($shorter$)$;

$\}$

else

$\{$

return false;

$\}$

$\}$

Question $19$ options:

There is no return value.

The code snippet returns false if the string is a palindrome.

The code snippet always returns false.

The code snippet returns true only for strings that contain only one character repeated any number of times.