Redbud Company uses a certain part in its manufacturing process that it buys from an outside supplier for $44 per part plus another $6 for shipping and other purchasing-related costs. The company will need 10,000 of these parts in the next year and is considering making the part internally. After performing a capacity analysis, Redbud determined that it has sufficient unused capacity to manufacture the 10,000 parts but would need to hire a manager at an annual salary of $40,000 to oversee this production activity. Estimated production costs are determined to be as follows: Direct material $ 28 Direct labor 12 Variable overhead 6 Fixed overhead (includes manager at $4 per unit) 10 Total unit cost $ 56 Required information Required: a. Identify the relevant costs to make this part internally. (Select all that apply.) Historical cost Direct labor Direct material Variable overhead Fixed overhead New manager's salary