An investor already has some money invested in Company A. She does not have any shares of Companies B and C. She has some extra money available, and she is deciding in which company to invest this extra money right now. The investor beliefs that the following scenarios are likely to occur one year from now:

a. With probability 1/2 the price of one share of Company A will be $100, one share of Company B will be $200, and one share of company C will be $50.
b. With probability 1/2 the price of one share of Company A will be $50, one share of Company B will be $400, and one share of company C will be $25.

In order to diversify her portfolio, the investor should invest in assets that have returns. In this case, the investor should use her extra money to purchase shares from company's: _____________