单选题

A There is no evidence showing that memory aids are invalid.

B Human beings’ brain functions mainly through memory aids in an effective way.

C Memory aids encourage an organised approach which helps the brain function effectively.

D Memory aids have little effect on the brain.

解析：
对话中男士提到scientific studies have proved that these aids encourage a very organised and methodical approach, which helps the brain to function effectively。故选项C正确。