The correct answer is external customers.
External customers are those who actively seek out, research, and buy, rent, or lease products or services offered by a business. They are the primary source of revenue for the business and their satisfaction is critical to the success of the business. Internal customers, on the other hand, are individuals or departments within the same organization who rely on the products or services of other departments to carry out their work. Suppliers are businesses or individuals who provide goods or services to another business, while investors provide capital to a business in exchange for ownership or a return on their investment.