4.3 What does the margin of error include? When a margin of error is reported for a survey, it includes
(a) random sampling error and other practical difficulties like undercoverage and nonresponse.
(b) random sampling error, but not other practical difficulties like undercoverage and nonresponse.
(c) practical difficulties like undercoverage and nonresponse, but not random sampling error.
(d) None of the above is correct.