What Information mainly does the following quotation convey?
R
"In study after study, of composers, basketball players, fiction writers, Ice skaters, concert planists, chess players, master criminals, and what have
you, this number comes up again and again. Of course, this doesn't address why some people get more out of their practice sessions than others
do. But no one has yet found a case in which true world-class expertise was accomplished in less time."
A. Ice skaters can achieve mastery more quickly than chess players.
OB. All people get the same results out of their practice sessions.
OC. The time required for mastery is consistent across a wide variety of skills.
D. Sometimes true world-class expertise can be achieved in fewer than ten thousand hours.