The correct answer is: D. individuals buying and selling the stock.
The market price of a share of common stock is determined by the supply and demand for the stock. When more people want to buy a stock than sell it, the price goes up. When more people want to sell a stock than buy it, the price goes down. The board of directors of the firm, the stock exchange on which the stock is listed, and the president of the company can all affect the supply and demand for a stock, but they do not directly set the price.
The board of directors of the firm can affect the supply of stock by issuing new shares or buying back existing shares. The stock exchange on which the stock is listed can affect the supply and demand for a stock by listing or delisting the stock. The president of the company can affect the supply and demand for a stock by making announcements about the company’s future prospects. However, ultimately, the price of a stock is determined by the individuals who are buying and selling the stock.