1–1 What are the three major types of product costs in a manufacturing company?1–2 Define the following: (a) direct materials, (b) indirect materials, (c) direct labor,(d) indirect labor, and (e) manufacturing overhead.1–3 Explain the difference between a product cost and a period cost.1–4 Distinguish between (a) a variable cost, (b) a fixed cost, and (c) a mixed cost.