3. Ella and Lilj are economics students who go to a yoga class together. Both have to choose how many classes to go to per week. Each class costs $20. The table below shows both students estimates of total benefits and total costs that they get from class each week. Total Benefit Marginal Total Benet Marginal Quantity of Classes for Ella benet for Lilj benet 0 $0 $0 1 23 23 2 42 50 3 56 65 4 64 72 (a) What is Ella's optimal number of yoga classes per week? Why