The correct answer is: A. Cross-Sectional Data
Cross-sectional data is data that is collected from a single source at a specific point in time. It is a snapshot of a population at a particular moment. For example, a survey of people’s income and education level conducted in a single year would be cross-sectional data.
Time series data is data that is collected over time from the same source. It can be used to track changes in a population or phenomenon over time. For example, a time series of the unemployment rate in the United States would show how the unemployment rate has changed over time.
Longitudinal data is data that is collected from the same individuals over time. It can be used to track changes in individuals over time. For example, a study that follows a group of children from birth to age 18 would collect longitudinal data on the children’s development.
Panel data is a type of longitudinal data that is collected from a sample of individuals over time. It is a combination of cross-sectional and longitudinal data. For example, a study that follows a sample of 1,000 people from age 25 to age 75 would collect panel data on the individuals’ health, income, and education level.