In the Figure Shown Below, the H-R Diagram for the Very

In the figure shown below, the H-R diagram for the very old cluster M55 shows the presence of an intriguing type of object, namely main-sequence stars bluer and more luminous than the turnoff stars.These stars have been called "blue stragglers," and an attractive explanation might be that they are

A) newly formed stars within in the very gas-rich globular cluster environment.
B) high-mass stars, recently formed by mergers of old, lower-mass stars in the densely packed cluster.
C) very luminous Type Ia supernovae at their peak luminosity.
D) exotic stars that produce energy by mechanisms other than nuclear fusion.
E) stars that do not belong to M55.