Answer:
The correct answer is letter "B": the ratio of sales revenue of the firm to the total sales revenue of all firms in the industry, including the firm itself.
Step-by-step explanation:
Market Share is calculated by taking sales of a company over a period and dividing it over the same period industry's total sales, including the company. This calculation serves to give a general idea of the size of the organization or segment relative to the consumers and the company's competitors.