Answer:
D. Sole proprietorship.
Step-by-step explanation:
We know it's definitely is a sole proprietorship because of 'unlimited personal liability' which is a key characteristic.
Selma's business is not a joint venture because she is the only person who invested and runs the business whereas a joint venture is created by two or more entities or 'shared ownership'
Nor is it a corporation for this is an 'organization' owned and manned by many people but is regarded as a single entity. Neither is her business an s corporation because that just the same as a corporation but just with different tax regulations.