Why Would a Nurse Researcher Opt to Use a Stratified

Why would a nurse researcher opt to use a stratified sample in a research study?

A) The sample population is divided into subsets that are homogeneous for a particular trait or feature.
B) The sample population is divided into subsets for random assignment into an intervention or a usual-care group.
C) The sample population is randomly assigned to a specific subgroup that will vary from the others on the basis of type of treatment.
D) The sample population is randomly assigned to a specific subgroup that will vary from the others on the basis of treatment duration.