Which of the following goods is best described as being sold in a monopolistically competitive market?

The persistent problem of inflation, beginning in the late 1960s, had its causes in all of the following except

(a) The full-scale entrance of the United States into the Vietnam War in 1965 (b) "Oil shocks" in the 1970s (c) Rising production costs in almost every sector in the economy due to rising energy costs (d) Rising corporate taxes which raised the cost of doing business

The figure below depicts the short-run market equilibrium in a perfectly competitive market and the cost curves for a representative firm in that market. Assume that all firms in this market have identical cost curves.In the long run equilibrium in this market:

A. price will equal $5, and there will be 20 firms in the industry. B. price will equal $5, and there will be 10 firms in the industry. C. price will equal $5 and total output will equal 500 units, but there is not enough information to determine how many firms will be in the industry. D. price will equal $8, and there will be 20 firms in the industry.