Adobe gives away the Acrobat Reader to build a market for the sale of software that creates Acrobat files. This is an example of:O a$.$ one market attempting to conquer a new market by making it a subset, component, or feature of its primary offering.O b$.$ markets, once considered distinctly separate, beginning to offer similar features and capabilities.O c$.$ firms taking advantage of complementary products developed for a prior generation of technology.O d$.$ firms spreading costs across increasing units of production or in serving multiple customers.Oe$.$ firms giving away products for half of a two$-$sided market to seed the market.