Identify the types of sampling errors that exist in the following sampling designs.

I. A radio show asks people to phone in their views on whether the United States should house the homeless.

II. The student newspaper plans to make a prediction for the student council election based on a survey of its readers.

III. A new gym chooses to survey the first 20 members who enter the facility one day to determine whether members favor the new elliptical machines.

a) I, voluntary; II, nonresponse; III, convenience

b) I, nonresponse; II, voluntary; III, convenience

c)I, nonresponse; II, convenience; III, voluntary

d)I, voluntary; II, convenience; III, nonresponse

e)I, convenience; II, voluntary; III, nonresponse