Answer: D. Incorrect; we do not know if the scale Mr. Cartman devised was valid or reliable but he was unethical
in presenting the measurement as "standard marketing research.
Step-by-step explanation:
Based on the information given in the question, the correct option is D "we do not know if the scale Mr. Cartman devised was valid or reliable but he was unethical in presenting the measurement as "standard marketing research".
He was unethical as he didn't tell his friends that he was collecting the information from them for a research purpose. Also, making up some of the issues regarding his research is not appropriate.
Therefore, the correct option is D.