Researchers Produce the Efficient Quantity of Research and Development If

Multiple Choice

Researchers produce the efficient quantity of research and development if they receive a voucher equal to the marginal ________ benefit,or a subsidy equal to the marginal ________ benefit. Patents and copyrights ________ result in an efficient amount of research and development.

A) social;social;cannot
B) social;social;can
C) external;external;cannot
D) external;external;can
E) external;social;can