Answer:
c. cross-sectional
Correct, by definition the cross sectional study "is a type of observational study that analyzes data from a population, or a representative subset, at a specific point in time" so for this case satisfy the condition required.
Step-by-step explanation:
a. longitudinal
False a longitudinal study by definition is "is a research design that consists on taking repeated observations of the same variables over short or long periods of time" and usually with the same individuals, and that's not the case since we are selecting people at some point of the time.
b. correlational
False a correlational study is in order to check if two or more variables present correlation but this study not take in count the time so for this case is not the correct option
c. cross-sectional
Correct, by definition the cross sectional study "is a type of observational study that analyzes data from a population, or a representative subset, at a specific point in time" so for this case satisfy the condition required.
d. biographical study
False this study is not related to the question of interest.