Answer
Total surplus if:
Barb buys from Courtney: 9
Bob buys from Carlos: 10
Bob buys from Chad: 5
Largest total surplus: Bob buys from Carlos
Work Step by Step
Total surplus if:
Barb buys from Courtney: 5 + 4 = 9
Bob buys from Carlos: 5 + 5 = 10
Bob buys from Chad: 5 + 0 = 5
Largest total surplus: both have the highest consumer and producer surplus, and adding them would give the highest total surplus
