(A) : Comets move around the sun in elliptical orbits. The gravitational force on the comet due to sun is not normal to the comet’s velocity but the work done by the gravitational force over every complete orbit of the comet is zero.
(R) : Gravitational force is a non conservative force.

• The sun's gravitational pull on the comet is a moderate pull. 
• The work performed by gravitational forces throughout each whole orbit of the comet is zero because, regardless of the type of path, the work performed by a conservative force over a closed path is always zero.

Hence the correct answer is ‘A’ is true and ‘R’ is false.