Select the option that can be used as a one-word substitute for the underlined group of words.

Rahul has done a study of statistics that contributed to the research.

The correct answer is Demography.

Let's break down the meaning of the underlined phrase, "a study of statistics that contributed to the research", specifically relating to human populations, as well as the meanings of all the given options:

1. Demography: The statistical study of human populations, including their structure, distribution, and trends over time. In this context, Rahul's study of statistics related to population data is best summarized by the term demography.

2. Choreography: The art or practice of designing sequences of movements of physical bodies in which components or motion are specified, especially in dance.

3. Cartography: The study and practice of making maps.

4. Cinematography: The art or science of motion-picture photography.

Therefore, the word Demography is the appropriate one-word substitute for the underlined group of words.