Question $19$

The function given in the text box bellow is expected

to return the sum of the elements of matrix $m.$ For

example mysum$([13$;$4-1])$ should return $7.$ A line is

missing; what is it$?$

a$)$ res $=$ res $+{\displaystyle \underset{?}{\overset{?}{}}}(m)$;

b$)$ res $=$ res $+m(i,j)$;

c$)m=$ res; break;

d$)$ res $=m(j,i)$;

e$)$ None of the above