Survey research on a sample at a single point in time, pertains to which of the following research designs?

Cross-sectional design studies a sample at one single point in time to capture a snapshot of the population.

Experimental design manipulates an independent variable and measures its effect, so it is not defined by single-time observation.

Longitudinal design observes the same subjects repeatedly across several time points to track change.

Case study makes an intensive in-depth study of one unit rather than a timed survey sample.

Cross-sectional surveys are quick and economical but cannot establish cause and effect over time.

Cohort and panel studies are common types of longitudinal design.