Select the true statements [ In the presence of negative externalities, a perfectly price discrimination seller is usually more efficient than perfectly competitive markets Public goods are non-excludable and non-rivalrous Inthe presence of externalities, perfectly competitive markets are efficient Inthe presence of negative externalities, monopolist markets are usually more efficient than perfectly competitive markets Public hospitals are an example of a public good When consumers are unsure about market prices, they tend to disconsider the total cost, and are more likely to purchase something, increasing market efficiency