$(5$p$)$ Consider a primal problem and its dual. Which of the below statement$($s$)$ is$($are$)$ correct?

i$.$ Unconstrained v$$riables in the primal appear as equality constraints in the dual.

ii$.$ Equality constraints in the primal appear as equality constraints in the dual.

iii. $$ constraints in the dual always appear as $$ constraints in the primal.

iv$.$ For feasible solutions; the objective values of the dual are always greater than the objective values of the primal.

A$.$ Only i

B$.$ Only ii

C$.$ Only iii

D$.$ ii and iii

E$.$ iii and iv