21.5 Saving for retirement. In 2014, a leading financial services provider conducted a survey in order to determine how Americans are planning for retirement. Of the 1017 adults aged 18 years and older who were included in the survey, 214 said they were currently not saving anything for retirement. Based on this information, the 95% confidence interval for the proportion of all adults who are currently not saving for retirement would be
(a) 0.155 to 0.265.
(b) 0.185 to 0.235.
(c) 0.197 to 0.223.
(d) 0.200 to 0.220.