When a researcher uses a stratified sampling technique, they: Option A select elements from heterogeneous subsets of the population Option B recognize the extent that subsets are homogeneous on stratified variables will generally result in homogeneity on other variables as well Option C realize that a stratified sample is likely to be less representative on a number of variables than a simple random sample Option D recognize the extent that subsets are heterogeneous on stratified variables will generally result in heterogeneity on other variables as well