Company ABC has limited resources to invest and is currently evaluating its investment opportunities for the coming year. The company plans to purchase a digitally controlled machinery to increase its production capacity in order to meet increasing demand. As technology evolves, the company is facing skill gap and plans to invest in workforce upskilling through employee training and development. However, employee's upskilling needs depend on their current skills and their role in the company. The company can also recruit professional outsiders by offering attractive salary packages. Which investment option is considered an independent project and why?