A company is considering investing in several projects. It could invest in multiple projects $($but not in a fraction of a project; that is$,$ a project will be completely undertaken or not at all.$)$ The attached Excel file provides a list of the $25$ projects, along with the NPV $($$ millions$)$ of these projects, the costs $($$ millions$)$ that would be incurred on each

of these projects in Years $1-4,$ and the land $($acres$)$ needed for each project. The company would like to invest in those projects that collectively maximize the NPV of these undertaken projects, subject to the following constraints on the total cost $($ $ millions$)$ of these projects.

Year $1$ cost $=400$

Year $2$ cost $=300$

Year $3$ cost $=250$

Year $4$ cost $=200$

Further, the total land usage should be $=300$ acres.

A$.$ Use Solver in Excel to identify which projects should the company undertake.

B$.$ Now suppose that the company faces an additional constraint: If it undertakes Project $18,$ it must also undertake Project $22.$ Use Solver in Excel to identify

which projects should the company undertake.