Ans. (b) Sample.
Reason: Census is more accurate in terms of results because it studies all units of population, but it is time consuming, expensive, and sometimes not feasible to use. As a result, sampling is preferable for the following reasons:
(i) Economical – Sampling entails the study of a subset of the population, which increases the cost. The sample size is small.
(ii) Time savings – A census survey takes a significant amount of time, whereas sample studies do not.
(iii) Less effort – Because only a subset of the population is studied, the investigator must expend less effort than in a census.
(iv) Considerable accuracy – While results from sampling may not be as accurate as in the case of sampling, the level of accuracy of these results can be established through statistical tests of significance and, if significant, can be applied in general to the entire population.