Dr Armando Wants to Study Sex Workers' Concerns About Their

Dr. Armando wants to study sex workers' concerns about their personal safety. She begins by contacting three sex workers through an online ad and invites them to participate in an interview. She then asks the sex workers to recommend other sex workers they might know to serve as participants in the research. What kind of sampling is Dr. Armando conducting?

A) Random
B) Convenience
C) Theoretical
D) Snowball