Which of the Following Is the Best Explanation for Why

Which of the following is the best explanation for 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 peoples' learning genes begin to deteriorate, which leads to long-term memory loss.