单选题 With regular exercise, the body builds up its levels of BDNF (brain-derived neurotrophic factor), and the brain's nerve cells start to branch out, join together and communicate with each other in new ways. This is. the process that underlies learning: every change in the junctions between brain cells signifies a new fact or skill that's been picked up and stowed away for future use. BDNF makes that process possible. Brains with more of it have a greater capacity for knowledge. On the other hand, says UCLA neuroscientist Fernando Gámez-Pinilla, a brain that's low on BDNF shuts itself off to new information,
What will happen if a person has a brain that's low on BDNF?

• A. He will be able to learn many new skills.
• B. He will forget all the information stored in his brain.
• C. He will be able to learn things quickly.
• D. He will not pick up new information quickly.