https://blogs.baruch.cuny.edu/eng2850kmwb/?p=231
C because a market research helps when you are buying something which he is (car) and this is a secondary resource because it is recommended by someone rather than them finding the research himself.
Cause and effect is a common way to organize information in a text. Paragraphs structured as cause and effect explain reasons why something happened or the effects of something. The cause and effect text structure is generally used in expository and persuasive writing modes.
Your question is bit unclear.
