Seventy-Year-Old Mikayla Is a Retired Police Officer

Seventy-year-old Mikayla is a retired police officer.She enjoys traveling with her husband,walking her dog,and reading newspapers to stay current with world events.Occasionally she acts as a guest speaker at a local police academy,and she recently began taking a class on English literature,a topic that has always interested her.People often ask her how she has managed to stay so healthy and active when others her age are experiencing mental and physical decline.She can tell them that

A) she is fortunate to have inherited good genes,since cognitive decline is very highly correlated with genetics.
B) people whose spouses are still alive invariably function at a higher level than those who are widows or widowers.
C) people who have good relationships with animals tend to have better overall intellectual health,particularly as they age.
D) she has kept her mind and body active because she knows she has to "use it or lose it."