A researcher plans to study the relationship between people's smoking behaviour and their tendency to have minor physical illnesses (such as colds or the flu) . Most likely she will use correlational research for the study because

A) correlational studies are always the "first choice" of researchers.
B) it is not practical or ethical to manipulate people's smoking behaviour.
C) correlational studies allow the researcher to draw strong cause and effect conclusions.
D) the university does not allow smoking in the psychology building.

It is not practical or ethical to manipulate people's smoking behaviour, as it would require either forcing them to smoke or forcing them to quit smoking. Therefore, a correlational study is the best option to observe the relationship between smoking behaviour and minor physical illnesses. Choice A is incorrect because correlational studies are not always the first choice, and other research methods may be used depending on the research question. Choice C is incorrect because correlational studies do not allow the researcher to draw strong cause-and-effect conclusions due to the lack of experimental manipulation. Choice D is irrelevant to the research question.