A:to persuade out of
B:persuading out of
C:being persuaded into
D:be persuaded into
一个圆环形跑道(如图),外沿的周长是314米,跑道的宽为2米,这个跑道要铺上沙子,每平方米需要沙子0.5吨,共需沙子多少吨?