3-28 Breakeven analysis; margin of safety (LO 1) The Stafford Company sells sports decals that can be personalized with a player's name, a team name, and a jersey number for $6 each. Stafford buys the decals from a supplier for $2.50 each and spends an additional $0.50 in variable operating costs per decal. The results of last month's operations are as follows: Sales revenue Cost of goods sold Gross profit Operating expenses Operating income $18,000 7,500 10,500 3,990 $ 6,510 Required a. What is Stafford's monthly breakeven point in units? In dollars? b. What is Stafford's margin of safety