Smyth Window has an order for $4$ products $(101,202,303,404.$ The company can assemble any or all these window products in$-$house or outsource their production to a partner company. The number of units required for each product are provided in the Smyth Window worksheet along with the unit costs to assemble the products in$-$house or to buy the products from partner.

If Smyth assembles the products in$-$house, there are three stages in this process: pick, assemble, inspect. The amount of time required for each product type in each of the three stages is given in the worksheet. Each of these three stages has a limitation on the total time available for this order.

The goal for Smyth Window is to minimize the total cost of filling the order. Which of the following are true?

There are four decision variables that correspond to the "Assemble" decisions in this problem.

There is a formulation with eight decision variables.

Ignoring nonnegativity constraints, there are seven constraints in total in this problem.

All constraints are "greater$-$than$-$or$-$equal$-$to$"$ constraints in this problem.