Which of the Following Most Accurately Defines a Probability Sample

Which of the following most accurately defines a probability sample?

A) A sample in which every element in the population has a known statistical likelihood of being selected
B) A sample arranged so that every element of the population has an equal chance of being selected as part of the sample
C) Any sample in which little or no attempt is made to get a representative cross section of the population
D) A sample using respondents who are convenient or readily accessible to the researcher-for example,employees,friends,or relatives