The Sketch Below Shows Groups of Stars on the H-R

The sketch below shows groups of stars on the H-R diagram labeled (a) through (e) .Note that (a) represents the entire main sequence while (c) and (d) represent only small parts of the main sequence.

-Which group represents stars with the longest main-sequence lifetimes?

A) A
B) B
C) C
D) D
E) E