Which Statement Offers the Best Explanation of Why Some Middle-Aged

Which statement offers the best explanation of why some middle-aged people have some long-term memory loss?

A) Middle-aged people have too much information stored;therefore,it is difficult to keep it all in long-term memory.
B) Middle-aged people have too much stress in their lives,which impedes their ability to use their long-term memory capacity.
C) Middle-aged people have less efficient retrieval skills for finding and retrieving information,even if the information was adequately stored in long-term memory.
D) Middle-aged people's learning genes begin to deteriorate,which leads to long-term memory loss.