A Relatively Fast Star Escapes an Open Cluster

A relatively fast star escapes an open cluster. What does this do to the stability of the remaining cluster?

A) The remaining cluster becomes MORE stable because only the slower stars are left.
B) The gravitational attraction of the escaping star tends to pull other stars after it, thus leading to the dissipation of the entire cluster.
C) The remaining cluster becomes LESS stable because the mass and thus the escape speed are reduced.
D) Because of the conservation of momentum, a second star must be expelled from the cluster in the opposite direction. The remaining cluster is then as stable as it was originally.