Which of the Following Is a Possible Explanation for Studies

Which of the following is a possible explanation for studies showing that as we age we experience deficits in our speed in performing new tasks but not in our memory of factual knowledge?

A) The deterioration of the myelin sheath over time reduces our ability to send neuronal messages quickly
B) The connections between neurons die out because we increasingly lose more neurotransmitters as we age.
C) As we age we continue to produce more neurons, making the information they code impossible to track.
D) all of the above