Which of the following is an example of nonrandom sampling?
A. Using a calculator's random function to generate 12 numbers and using those numbers to choose 12 people from a numbered list.
B. Sampling people with the last name Anderson by randomly picking a person in the phone book with the surname Anderson, then calling every twentieth Anderson after that until you've call 15 people.
C. Conducting a survey among the teachers at your school by asking your six favorite teachers.