As a Cluster of Stars Begins to Age, Which Type

As a cluster of stars begins to age, which type of star in the cluster will move off the main sequence of the H-R diagram first?

A) all the stars in a cluster are born at the same time; so they will all move off the main sequence at the same time, as they evolve
B) G type stars, like our Sun
C) M type stars, which are the coolest
D) the lowest mass stars, which have the least amount of fuel for fusion
E) the O and B type stars