If the marginal benefit of one more unit of a public good is $500 for Sam and $300 for Alex, the social benefit of one more unit of a public good is: Group of answer choices $300 since the benefit will go to the person who values it least. $800 since the benefit of one more unit goes to both individuals. $400 since that is the average benefit. $500 since the benefit will go to the person who values it most.