The nurse is critiquing a qualitative research study. Which question would be appropriate for the ...

The nurse is critiquing a qualitative research study. Which question would be appropriate for the nurse to ask when critiquing the study's methodology?
 
  a. Are the informants who were chosen appropriate to inform the research?
  b. If a particular approach is used to guide the inquiry, does the researcher complete the study according to the processes described?
  c. Does the researcher address the credibility, auditability, and fittingness of the data?
  d. Does the researcher place the report in the context of what is already known about the phenomenon (e.g., the existing literature)?