One can type better if he is relaxed because______.A．his muscles and nerves have learned t

One can type better if he is relaxed because______.

A．his muscles and nerves have learned to do the job well

B．this skill requires concentration on the details while typing

C．man was born with this kind of skills inbuilt

D．he can better exercise his authority over the fingers

请帮忙给出正确答案和分析，谢谢！