Final answer:
The legal theory that would allow Repair Garage to be sued by the customer is apparent authority.
So the correct answer is option C Apparent authority.
Step-by-step explanation:
The legal theory that would allow Repair Garage to be sued by the customer is c. Apparent authority. Apparent authority refers to the authority that a person or entity appears to have based on the actions, words, or conduct of another person or entity.
In this case, by allowing Joe to print business cards with the company's name and his title as a certified mechanic, Repair Garage created the impression that Joe had the authority to represent the company and perform repairs on their behalf.
As a result, the customer had a reasonable belief that Joe was authorized by Repair Garage, and therefore Repair Garage can be held liable for Joe's actions.