The Mounted Color Guard members are active duty Marines who volunteer their time evenings, weekends and holidays to perform these duties, in addition to their regular duties. The unit practices twice weekly. In 1999, the unit participated in 84 parades, ceremonies, horse clinics and rodeos in the western United States. They are active with public schools and programs.

Which sentence BEST concludes what the supporting evidence suggests in paragraph 6?
A) Some Marines are required to function as Mounted Color Guards.
B) The wild horses that participate must have a very good rapport with his/her handler.
C) Mounted Color Guards are retired marines that work part-time to train and show the horses.
D) Marines who participate as Mounted Color Guards also carry out their regular duties as U.S. Marines.