Final answer:
Rachel is a shareholder of GM Cube Inc. since she owns a large portion of the company's stocks. Shareholders are individuals who own shares in a corporation, representing ownership in the company.
Step-by-step explanation:
Rachel, by owning a substantial amount of GM Cube Inc.'s stocks, takes on the role of the company's shareholder. Shareholders, or stockholders as they are sometimes called, are individuals who own shares in a corporation, representing a piece of the company's ownership. Since Rachel does not work for the company, she does not fill the roles of a stakeholder in a broader sense, a board member, or a CEO, all of which would require different forms of engagement with the company. An individual with a majority or complete stock ownership in a company like GM Cube Inc. would command significant control or ownership over the company; however, in most large corporations such as IBM, AT&T, Ford, and General Electric, no single shareholder has such a majority stake.