There are four potential suppliers of haircuts. John . Sidney , Susan and Dan are each willing to provide one haircut. Their respective opportunity costs are : $4. $8. $12. and $16. There are four potential consumers of haircuts. Cheng . Wendy Trevor and Chris are each willing to purchase one hair cut. Their respective willingness to pay are: $20. $16. $12 and $8 In a competitive equilibrium the total surplus will be At: $12 - \\ 8. $16 ' C. $24 D. $8 E. Zero