Which of the following best describe a researcher striving for rigor i

Which of the following best describe a researcher striving for rigor in a study? The researcher has:

a. created a minimally controlled study design, to depict a more natural setting.
b. developed an instrument especially for this study to precisely measure anxiety.
c. found a highly reliable and valid instrument used in several previous studies with good results.
d. recruited 1000 qualified nursing students to participate in the study.

ESSAYBID ANSWER

ANS: C
A rigorously conducted quantitative study has precise measuring tools, a representative sample, and a tightly controlled study design.
Creating a tightly controlled design will help show causality between dependent and independent variables.
If it is a researcher-developed instrument, the validity and reliability are in question.
It does not say how the sample was selected, so it is not known if it is representative.