For each of the following, determine whether the group is a sample or

 

For each of the following, determine whether the group is a sample or a population.

 

a. The participants in a study of a new cholesterol drug.

 

b. The drivers who received a speeding ticket in Kansas City last month.

 

c. Those on welfare in Cook County (Chicago), Illinois.

 

d. The 30 stocks reported as a part of the Dow Jones Industrial Average.