Elizabeth Is Noticing That Her Eighty Year-Old Grandfather Has Been

Elizabeth is noticing that her eighty year-old grandfather has been very forgetful the last few weeks. When he took her to the park the other day, he forgot where the car was parked when it was time to leave. He also talks more and more about his time in the war when he was a young man. Elizabeth thinks it is quite remarkable that he can remember things from fifty years ago, while he can't even remember where he parked the car an hour earlier. What Elizabeth is detecting may be

A) the onset of a dissociative disorder
B) the development of chronic depression
C) generalized anxiety disorder
D) the onset of senile dementia