onsumer surplus plus producer surplus is equal to:willingness-to-sell.marginal cost.total surplus.willingness-to-pay.

Consumer surplus plus producer surplus is equal to total surplus.

Here's a step-by-step explanation:

1. Consumer Surplus: This is the difference between what consumers are willing to pay for a good or service and what they actually pay. It's a measure of the benefit consumers receive from buying a good or service.

2. Producer Surplus: This is the difference between the price a producer actually receives and the minimum price they would be willing to sell their good or service. It's a measure of the benefit producers receive from selling a good or service.

3. Total Surplus: This is the sum of the consumer surplus and the producer surplus. It's a measure of the total benefit to society from the production and consumption of a good or service.

So, consumer surplus plus producer surplus equals total surplus.