"Grandpa Is 88 Years Old,and He Has No Sign of a Neurocognitive

"Grandpa is 88 years old,and he has no sign of a neurocognitive disorder," says a friend of yours.Your MOST accurate comment is:

A) That's wonderful-about half of people that age do have signs of neurocognitive disorder.
B) That's wonderful-about a third of people that age do have signs of neurocognitive disorder.
C) That's wonderful-about 10 percent of people that age do have signs of neurocognitive disorder.
D) That's wonderful-about 5 percent of people that age do have signs of neurocognitive disorder.