In an AOL survey of Internet users, this question was posted online: “Have you ever been hit by a computervirus?”

In an AOL survey of Internet users, this question was posted online: “Have you ever been hit by a computer
virus?” Among the 170,063 responses, 63% answered “yes.” What term is used to describe this type of survey
in which the people surveyed consist of those who chose to respond? What is wrong with this type of sampling
method?
HERE
What term is used to describe this type of survey? Select all that apply.
A. The respondents are a voluntary response sample.
B. The respondents are a census.
O C. The respondents are a population
D. The respondents are a self-selected sample.