4. a. In year 1 the Consumer Price Index (CPI) is 120, and in year 2 the CPI is 135. If Mr. Gentleman's salary was $55,000 in year 1, what is the minimum salary he must earn in year 2 to "more than keep up with inflation"? Assume that the salary increase must keep the same rate as inflation. Show the calculation. i) $63,875 ii) $62,875 iii) $61,875 iv) $61,985 b. Why is the De Beers diamond monopoly a classic example of a monopoly? Select the correct answer and explain. i. It is government-created. ii. It arises from the ownership of a key resource. iii. It results in very little advertising of the product that the monopolist produces. iv. It was broken up by the government a long time ago. c. Select the correct answer and explain. A monopolist produces: (i) less than the socially efficient quantity of output and at a lower price than in a competitive market. (ii) less than the socially efficient quantity of output and at a higher price than in a competitive market. (iii) more than the socially efficient quantity of output and at a higher price than in a competitive market. (iv) the socially efficient quantity of output and at a higher price than in a competitive market