Bill and Krista sell potted plants from a roadside stand. The figure above shows Bill and Krista's marginal cost curve and the market price. If Bill and Krista sell 60 plants per week, their producer surplus from the 60th plant will equal
◦ $8.
◦ $480.
◦ $0.
◦ $20.
◦ More information is needed to answer the question.