The Employees of a Firm Refusing to Continue Employment with a Foreign

The employees of a firm refusing to continue employment with a foreign firm or buy products from the firm on account of conflicts between the union and the employer is an example of a(n) :

A) tariff on the goods.
B) embargo imposed by the government.
C) boycott called by the union.
D) method of avoiding an unfavourable exchange rate.
E) quota used to minimize foreign goods.