Please help me with the following ASAP;

1. Which of the following describes a situation where the marginal social benefit is equal to the marginal social cost at equilibrium? Oligopoly Monopoly Positive externality Allocationficiency Negative externality 2. A market in which private consumers are not the only beneficiaries of their purchase represents a and will result in than the socially optimal quantity. negative externality; less negative externality; more positive externality; more positive externality; less natural monopoly; less