In 2020, Ingram Corp. is a small start-up manufacturer. It has one machine capable of producing 100,000 units per year. Ingram currently produces just 1000 to 2000 units per month. The machine cost is a step cost, but it can be reasonably modeled as which type of cost? Select one: O a. fixed O b. variable In 2028, Ingram has massively grown and now produces 5 million to 10 million units per month. The machines are essentially the same as in 2020. Machine cost can be reasonably modeled as what in 2028? Select one: O a. fixed b. variable