A planet moves in an elliptical orbit around a star, as shown in the diagram. Which of the following is true as the planet moves from position 1 to position 2?
А.The planet loses kinetic energy due to negative gravitational work; thus, the total energy in the planet-star system decreases.
B.The planet's kinetic energy increases due to positive gravitational work; thus, the total energy in the planet-star system increases.
C.Kinetic energy decreases and gravitational potential energy increases, but the total energy in the planet-star system stays constant.
D.Potential energy decreases and kinetic energy increases, but the total energy in the planet-star system stays constant.