MINI-CASE Sparks Inc. ,A Firm That Manufacturers Low Voltage Halogen Lamps,currently

MINI-CASE
Sparks Inc. ,a firm that manufacturers low voltage halogen lamps,currently has a 40% share of a 1 million unit market.The firm has extensive customer knowledge,as well as extensive competitor knowledge.The three largest competitors of Sparks Inc.have market shares of 5%,10%,and 15%,respectively.
-Mini-Case Question.The percentage cost of goods sold by Sparks Inc.is 40%.The percentage cost of goods sold by its three largest competitors is 30%,30%,and 20%.What is the cost advantage index of Sparks Inc.?

A) 80
B) 120
C) 43
D) 150
E) 62