There are 7 firms in a given market. Their respective market shares are the following:

(s₁,...,s₇) = (10%, 5%, 30%, 5%, 15%, 10%, 25%)

The market price for the good being sold is p = 100 and the firms' respective marginal costs are the following:

(MC₁,...,MC₇) = (80, 90, 25, 90, 60, 80, 40)

Determine the following measure of market power:

The Lerner Index for the market:

0.515

0.485

0.336

0.664