If You Plot the Positions of Thousands of Stars on the H-R

Multiple Choice

If you plot the positions of thousands of stars on the H-R diagram, most of those stars fall along the main sequence. Why are so many stars found along this line rather than in other parts of the diagram?

A) A star will remain a main sequence as long as there is enough atomic power.
B) High-mass stars are so massive that they will consume their fuel slowly.
C) A star will remain a main sequence as long as there is enough fuel to consume.
D) A low-mass star will consume its fuel and the star is so small that fuel will run out quickly.