With Reference to Systematic Sampling,which of the Following Defines Selection

With reference to systematic sampling,which of the following defines selection interval?

A) It is the idea that a study's results will tell us something about a group larger than the sample from which the findings were generated.
B) It is the principle that all elements in a researcher's target population have an equal chance of being selected for inclusion in the study.
C) It is the extent to which a sample represents its population on a particular parameter.
D) It is the individual unit that is the focus of a researcher's investigation.
E) It is the distance between elements selected for inclusion in a study.