Many adults think that a regular pocket money is a good way

Many adults think that a regular pocket money is a good way to teach children ...求解答
Many adults think that a regular pocket money is a good way to teach children the value of money.With ¥200 every month,we can know Yuanyuan's money kept in the bank is__________ less than used for food every half a month.
A.¥5 B.¥10 C.¥20