Answer:
C. Snowball
Step-by-step explanation:
Snowball sampling, in statistics, is described as a sampling method in which various research participants or subjects tends to recruit or select other members, participants, or subjects for a particular study or test. Snowball sampling is being used by the researcher when 'potential participants' are generally hard to find. It is referred to as snowball sampling because it collects more and more participants as it moves ahead.
The correct answer is snowball sampling.