DCR Ltd. manufactures a part used in several of its engine models. Monthly per unit production costs for 1,000 units are provided in the table below. It is estimated that 10% of the fixed overhead costs will no longer be incurred if the company buys from an outside supplier. The cost to purchase the part from the supplier is $85 per unit. If DCR purchases 1,000 parts from the outside supplier per month, its monthly net income will: a. increase by $13,000. b. increase by $15,000. c. decrease by $5,000. d. decrease by $3,000. Direct materials $40 Direct labour $10 Variable overhead costs $30 Fixed overhead costs $20 Total costs $100