According to Einstein's 1915 theory of general relativity, gravity...

• A. is a force at a distance like Newton
• B. is curved space
• C. is caused by dark matter
• D. is an illusion

Answer: (B)

In Einstein’s general relativity, gravity is not a force acting at a distance. Instead, mass and energy tell spacetime how to curve, and objects move along the straightest possible paths in that curved spacetime (geodesics). This curvature of spacetime guides the motion we perceive as gravity. So describing gravity as curved space (or curved spacetime) is the correct, modern picture.

The older Newtonian view treats gravity as a force at a distance between bodies, which general relativity replaces. Dark matter is a form of matter that can influence gravity through its own mass, but it doesn’t define gravity itself. And gravity isn’t an illusion—the effects of spacetime curvature are real and observable, like the bending of light around massive objects.