When the Stars of the Following Open Clusters Are Plotted $\chi$

Multiple Choice

When the stars of the following open clusters are plotted on an H-R diagram, the temperature values for the turning points are approximately: Coma (10,000 K) , h + $\chi$ (40,000 K) , M67 (7500 K) , and Pleiades (20,000 K) . Which cluster is oldest?

A) Coma
B) h + $\chi$
C) M67
D) Pleiades