Which of the following is not a source of demographic data?

Answer: Option C

Traveller's accounts are not a source of demographic data.

In social demography, demographic data typically come from sources such as censuses, administrative records, and sample surveys.

Censuses provide comprehensive data on population characteristics, while administrative records contain information collected by government agencies, such as birth and death registrations.

Sample surveys involve collecting data from a subset of the population to estimate characteristics of the entire population.

Traveller's accounts, while they may contain anecdotal information about populations encountered during travel, are not systematic sources of demographic data and are therefore not considered a primary source in social demography.