After executing the following code, what is the value of $B?$

$A=$ ones $(4,4)$;

for $c=1$:$4$

for $r=1$:$4$

if $r==c$

$A(r,c)=2$;

else

$A(r,c)=1$;

end

end

$B=A($:$,1)$

A$)[112211$