Which of the following actions of a firm suggests that it uses the freemium approach for applying freeconomics? a. It distributes products to customers without an appreciable cost to anyone. b. It reduces the sale price of one item in order to sell something else of value. c. It provides free services to customers and gets paid for it by third parties. d. It offers basic services for free, but charges a premium for special features. e. It allows people to participate and collaborate to create something of value.