Answer: sector.

The correct answer is **A. sector.** In the GICS, each company is assigned to a sub-industry based on its principal business activity. Sub-industries are grouped into industries, industries into industry groups, and industry groups into sectors. As of June 2009, the GICS structure included 10 sectors, making it the broadest level of classification. Options B and C are incorrect because industries and industry groups are narrower classifications within the GICS hierarchy.

Author: LeetQuiz Editorial Team