Answer:
b. A very large increase in sales. A very rapid and similar response by the other large firms in the industry.
Explanation:
As for the information there is no clear agreement to sell the goods at the same price, like that of other industries.
Further since all the companies follow the same price, there is no such differentiation.
In case one of the companies, in our case company A if decreases the price then it will abruptly that is in no clear sequence will increase its sales, and the after effects will also include the decrease in prices by other remaining industries that is B, C and D.