If the following script was run in MATLAB, what would be the value of Sum?

$A=[1,2,3$;$4,5,6$;$7,8,9]$

for $r=1$:$3$

Sum $=0$

for $c=1$:$2$

Sum $=$ Sum $+A(r,c)$;

end

end

$8$

$45$

$15$

$27$