What Would Be an Appropriate Rationale for a Nurse Researcher

What would be an appropriate rationale for a nurse researcher to exclude subjects who have diabetes mellitus,are older than age 60 years,or who are HIV positive from a descriptive study examining the characteristics of chemotherapy-induced peripheral neuropathy?

A) Mortality as a threat to validity is increased when including subjects with multiple health problems.
B) The exclusion conditions are also associated with the development of peripheral neuropathy.
C) The researcher has limited resources to conduct the study.
D) The researcher has all of the exclusion characteristics.