Why Does the Hertzsprung-Russell Diagram of a Globular Cluster NOT

Why does the Hertzsprung-Russell diagram of a globular cluster NOT contain any stars with high luminosity and high temperature on the main sequence?

A) These high-mass stars evolved away from the main sequence long ago.
B) Stars that will occupy this position on the main sequence have not yet evolved there from the protostar stage.
C) The stars that were in this position on the main sequence have undergone splitting into binary stars and hence appear lower down on the diagram.
D) This type of cluster contains only low-mass stars and has never had high-luminosity stars on its main sequence.