Comets mover around the sun in highly elliptical orbits. The gravitational force on the comet due to the sun is not normal to the comet’s velocity in general. Yet the work done by the gravitational force over every orbit of the comet is zero. Why?$

• A. The gravitational force is conservative, hence work done is zero
• B. The gravitational force is non-conservative, hence work done is zero
• C. Energy is absent, hence work done is zero
• D. Force is in negative direction