Which of the following is an example of random sampling?
A.
Migrant workers are surveyed on their opinion of mandatory health insurance for companies.
B.
The school newspaper asks teachers in that middle school how they feel about the behavior of twelve year old boys.
C.
A national survey company picks one phone number from each area code in America to call and ask for an opinion on current political issues.
D.
The manager of a restaurant asks customers their opinion on a new salad dressing.