Product A requires 7 minutes of milling, 7 minutes for inspection, and 6 minutes of drilling per unit; product B requires 10 minutes of milling, 5 minutes for inspection, and 8 minutes of drilling per unit; product C requires 4 minutes of milling, 3 minutes for inspection, and 15 minutes of drilling. The department has 18 hours available during the next period for milling, 15 hours for inspection, and 24 hours for drilling. Product A contributes $2.0 per unit to profit, product B contributes $2.3 per unit, and product C contributes $4.0 per unit. How do you express the milling constraint mathematically? NOTE: Let A,B, and C denote respectively the number of A, B, and to be produced. O a. 7 A+ 10 B+ 4C