Final answer:
The owner of the restaurant's decision to prepare steaks based on past sales is an example of a research hypothesis.
Step-by-step explanation:
The owner of the restaurant basing the number of steaks prepared on the fact that he sold 12 steaks last Friday and most of the customers were regulars is an example of C) A research hypothesis. When making this decision, the owner is hypothesizing that the number of steaks sold last Friday accurately represents the demand for steaks on future Fridays, assuming that the customer base remains the same. This decision is based on a hypothesis, rather than quantitative or qualitative research, or convenience sampling.