Affinity Toasters produces top-quality bagel and bun toasters.The Jessie Princess production process requires four sequential activities, construction, burner insertion, polishing, and packaging. Construction can make 100,000 toasters per day; burner insertion can install 25,000 burners every 6 hours,polishing can finish 3000 toasters every half hour, and packaging can finish 5,000 per hour.Which activity is the constraint?