Two goods must have infinite cross elasticities to be considered as belonging to the same market

Suppose there are ten firms that occupy the Odell, Oregon cherry pie market. The market share of each firm is listed in the above table

a) What is the four-firm concentration ratio in this market? b) What is the Herfindahl-Hirschman Index for this market? c) If Firm H and Firm A merge, what is the new Herfindahl-Hirschman Index for this market? d) A severe winter causes every firm except A, B, and E to close. With only these three firms operating, Firm A's market share is 71 percent, Firm B's market share is 23 percent, and Firm C's market share is 6 percent. What is the Herfindahl-Hirschman Index for this market now?

A negative externality is a situation in which

A) there is a spillover of benefits. B) a cost associated with an economic activity is borne by a third party. C) a firm is paying in excess of the total costs of producing a good. D) none of the above.