Business ethicist: Managers of corporations have an obligation to serve shareholders as the shareholders would want to be served. Ttherefore, corporate managers have an obligation to act in the shareholders' best interest. The business ethicist's conclusion follows logically if which one of the following is assumed? ['Shareholders would want to be served only in ways that are in their own best interest.', 'Corporate managers are always able to discern what is in the best interest of shareholders.', 'All shareholders want to be served in identical ways.', 'The shareholders have interests that can best be served by corporate managers.']