Refer to Model $5$S$\mathrm{.}4$ in your text. Check also the course slides. Which of the following is true? A$.$ The term in the objective function means that supply location ships either quantity or nothing. B$.$ The term in the objective function means the cost of meeting the demand of location from supply location C$.$ The term in the objective function accounts for the fixed cost of establishing $($or operating$)$ a supply facility at location D$.$ For an instance with $3$ supply locations and $4$ demand locations, is a valid supply constraint. E$.$ All of the above.