What is the main characteristic of a census in statistical terms?

A census in statistical terms is defined as a complete enumeration of every member of a population. This means that every individual within the population is measured or accounted for, ensuring that the data gathered reflects the entire group without any omissions. By collecting data from all members, a census aims for the highest level of accuracy and comprehensiveness possible, providing a full picture of the population's characteristics.

In contrast, the other options describe processes that involve only a portion of the population rather than the whole. This includes focusing on small samples, collecting data from subsets, and utilizing sampling techniques, which all lead to estimates rather than exact counts. By differentiating a census from these methods, it’s clear that a census is unique in its goal of complete coverage, making option C the correct choice.