The correct response is:
Theory, because it has overwhelming evidence supporting it.
Gravity is considered a scientific theory because it is supported by extensive experimental and observational evidence. Unlike a hypothesis, which is a preliminary assumption subject to testing, a scientific theory explains a broad range of phenomena and has stood up to rigorous scrutiny and testing over time. Theories can be revised or rejected if new evidence arises, but the theory of gravity is well-established and widely accepted within the scientific community.