The exclusive right to display a symbol of product identification is a:
a. patent.
b. copyright.
c. trademark.
d. franchise.

c. Trademark.

Explanation:

it is a termed used for identification of signed or design of some particular corporation. sometimes trademark become more famous than  corporation therefore main motives behind trademark is to used as a symbolization of corporation. It is used to protect the original design of the company and brand name.

answer; is usually (less than) the socially optimal level of consumption;