Answer:
b. Market share ratio
Step-by-step explanation:
When the sizes of firms of a particular sector/market are being compared, a common basis for comparison is on the basis of total sales, a larger firm will have a higher ratio of total sales in the sector.
The "concentration ratio" is derived from the market shares. It gives the sum of market shares of the few largest firms in the sector, and is a measure of market power. It is not the correct choice in this case.