I've been stuck on this question please help :((( Which statement(s) apply to stratified random sampling? Check all that apply.

A) It can provide better estimates than a simple random sample.
B) The researcher needs some knowledge of the population in terms of characteristics relevant to the study.
C) A challenge is that it is necessary to have strata of the same size.
D) Creating strata of similar individuals to sample from reduces variability.
E) It can be difficult to obtain with a very large population.