HELP PLEASE BRAINLEST FOR ANSWER Which sample is biased? Which is not baised
A.
A book store owner surveys 50 customers to find out if they like to read.

B.
Two students survey 100 people on the street asking for their favorite soda.

C.
A phone system randomly calls people living in a city asking for their favorite store.

D.
A computer program randomly emails a survey to customers to see if they are satisfied with the service.