Consider the following $3$ programs:

$123$

$//$contents of file foo.c: static int a $=5$; int main$()\{$ f$()$; return $0$; $\}//$contents of file bar.c: static int a $=10$; void f$()\{$ printf$("\%$d

$",$ a$)$; $\}$

$//$contents of file foo.c: int a $=5$; int main$()\{$ f$()$; return $0$; $\}//$contents of file bar.c: extern int a; void f$()\{$ printf$("\%$d

$",$ a$)$; $\}$

$//$contents of file foo.c: static int a $=5$; int main$()\{$ f$()$; return $0$; $\}//$contents of file bar.c: int a; void main$()\{$ printf$("\%$d

$",$ a$)$; $\}$

If the command $"$gcc foo.c bar.c$"$ is executed, which of the above programs result in a linker error?

Group of answer choices

$3$ only

$2$ and $3$

$1$ only

$1,2,$ and $3$

$1$ and $2$

$2$ only