Before Airbnb existed, the website CouchSurfing makes it possible to reserve a "bed" in someone else's home. One catch was that the host was not allowed to charge for lodging. The creation of Airbnb created a marketplace for private lodging where prices are greater than zero.

(a) Explain which groups of consumers are most likely to have a large surplus from the existence of Airbnb relative to hotels. Your answer should focus on the concepts of elasticity and substitutability of hotels and Airbnb rentals. Illustrate your argument using two demand curves.