What Would Happen If a Sociologist Used Purposive Sampling to Select

What would happen if a sociologist used purposive sampling to select a case for a historical-comparative research study? He or she would

A) reduce validity in order to gain the benefit of a highly focused study.
B) choose a case because it represents an anomaly (something different than what is typical) .
C) identify all possible cases and select one at random (to reduce bias) .
D) review the literature and identify the case with the most need for critique and revision.