Consider the following functions:

void foo $($ int length $)\{$

foo $($length$,"")$;

$\}$

void foo $($ int length, String seq $)\{$

if $($seq$.$length$()==$ length $)\{$

System.out.printf$("\%$s

$",$ seq $)$;

return;

$\}$

if $($seq$.$length$()!=0)\{$

String seq$0=$ seq $+"0"$;

foo$($ length, seq$0)$;

$\}$

String seq$1=$ seq $+"1"$;

foo$($ length, seq$1)$;

$\}$

What is the last string that is printed when we call foo$(4)?$

$0000$

$0001$

$1000$

$1111$

$1110$

$0111$

none of the above