C. Limited unregistered business is not a principal form of business organization. This type of business formation does not exist. Partnerships, sole proprietorship and corporations are all valid forms of business organizations.

A sole proprietorship is a business that is run by a single owner. The owner is personally responsible for any debts and taxes incurred by the business. However, this is the simplest form of business to create since it only requires a local city license to start formal operations.

A partnership is a business that is run by two or more individuals. This type of business formation requires more time to set up. The basis of each individual's ownership must be agreed to. It is advisable to create a legal document that states the rights and obligations of each participant in the partnership.

A corporation is formed as its own entity. It is owned by shareholders, and a management team is appointed to run the business operations. However, the individuals who invest in or run the company are not legally responsible for the company's debts.