Answer:
C. additional information
Step-by-step explanation:
When you gather data, the most important thing that you need to fill first is the identity of the subjects.
In business, the data that companies take through questionnaires is made in order to read the market's trends or customers' general preference. In order for the data to be usable, the companies need to be able to differentiate subjects based on different characteristics (such as age, gender, income level, etc). All of this information is filled under the additional information box on every files.