Which of the following is the best general definition of a random sample?
A) A subset of the population, that is selected so that only the most easily accessible elementary units are chosen for observation.
*B) A subset of a population, chosen in such a fashion that begins with a randomly selected individual and then selects a subset systematically.
C) A subset of a population selected with the help of some randomizing device that assures each unit a known and equal probability of selection.
D) A subset of a population, chosen by observing all members of separate randomly chosen subsets of geographically distinct clusters into which the population is naturally divided.