A cell phone provider offers corporate plans to businesses

Question

For each of the cases below, explain whether they represent a type of price discrimination or not and, if they do, which type.

1. As you enter a store you see a sign saying "buy 2 get 1 free".
2. A motel charges a higher price for a room to customers with dogs or cats than to
3. customers with no pets.
4. A cell phone provider offers corporate plans to businesses and individual plans to non-business customers.