What key problem of other modes of research does unobtrusive

What “key problem” of other modes of research does unobtrusive research resolve? a. Validity isn’t an issue in unobtrusive research. b. Other modes involve potential effects of the measurement upon what’s being measured. c. Unobtrusive methods have no unique advantages; they just create more problems. d. Reliability isn’t an issue in unobtrusive research.

Solution

Answer: b. Other modes involve potential effects of the measurement upon what’s being measured

Reason: Unobtrusive research is free from Hawthorne effect, that is the effect of research on the subjects. This effect is present in almost all of other modes of research.