The Herfindahl-Hirschman Index Measures Market Structure as The

The Herfindahl-Hirschman index measures market structure as the:

A) sum of the squared market shares of the 10 largest firms in an industry.
B) sum of the squared market shares of all firms in an industry.
C) sum of the squared market shares of the four largest firms in an industry.
D) squared market share of the largest firm in an industry.
E) sum of the market shares of the four largest firms in an industry.