Final answer:
People are kept from lying about family numbers when getting water by being counted by officials, akin to census-taking or the mark and recapture method used in wildlife tracking.
Step-by-step explanation:
The method by which people are kept from lying about the number of family members they have when obtaining water can vary. Option (c), counted by officials, would be a direct way to enforce accuracy, similar to methods used for population counting or voter registration.
In the case provided, a procedure akin to the mark and recapture method of tracking animal populations or the census taken for human populations could be used to ensure truthful reporting. These methods rely on accurate counts rather than mere declarations, thus reducing the potential for dishonesty.