If the Stars at the Turnoff Point of a Cluster $3.0×10^{10}$

Multiple Choice

If the stars at the turnoff point of a cluster have a mass of 3M, what is the age of the cluster

A) $3.0×10^{10}$ years
B) $3.3×10^9$ years
C) $6.4×10^8$ years
D) $1.6×10^{11}$ years
E) The age of a star cluster cannot be determined from the mass of stars at the turnoff point.