Eighty-Seven-Year-Old Miriam Hansen Has Amazed Her Friends and Relatives by Taking

Eighty-seven-year-old Miriam Hansen has amazed her friends and relatives by taking college classes.Not only does she enjoy them,but she does well.In fact,she actually seems to have become brighter since she began studying.How can we account for this?

A) Miriam has probably learned how to improve her reasoning skills.
B) Miriam probably always was very bright,but this didn't become obvious until she did her college work.
C) Miriam has strengthened her cognitive mechanics,which research shows is possible in old age.
D) Miriam has developed "college" wisdom,something that happens with older but not younger people.