On National Day, Jack, a middle school student, went to Harbin Wanda Amusement Park with his three classmates. According to the price list, they saved________ of the cost on usual days.

Adult (age 60 and above)	Adult (age under 60)	Child (age 6-17)	Child (age under 6)
Free	￥200	￥150	Free
October 1st: 20% off

A、￥480

B、20%

C、two fifths