In the Hertzsprung-Russell Diagram, How Does the Position of a Typical

In the Hertzsprung-Russell diagram, how does the position of a typical star change while it is at the main-sequence phase of its evolution?

A) Stars move from upper right to lower left while they are on the main sequence.
B) Stars move from upper left to lower right while they are on the main sequence.
C) Massive stars (4 solar masses) move toward the upper left as their luminosity increases, while lower-mass stars move toward the lower right as their temperature decreases.
D) A star's position on the main sequence is determined only by its mass, not its age, so stars do not move significantly along the main sequence during evolution.