Firms Free Ride on the Research and Development of Other

Firms free ride on the research and development of other firms when they

A) buy a firm's newly developed product, and then give it away to consumers.
B) use knowledge other firms have developed without paying for that knowledge.
C) license a new technology from a firm that developed the new technology.
D) choose a level of research and development that is inefficiently high.
E) file a patent with the appropriate government.