SSE JE Electrical Engineering 24 March 2021 Shift 2 Paper

An observatory is a location used for observing terrestrial, marine, or celestial events. All the data in the observatory collecting by Astronomer.
Similarly;
A laboratory is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. All the work in the laboratory is done by Scientists.
Hence, "Scientist : Laboratory" is the correct answer.