The nurse is teaching parents how to reduce the spread of impetigo. The nurse should encourage parents to （）.

A．teach children to cover mouths and noses when they sneeze.

B．have their children immunized against impetigo.

C．teach children the importance of proper hand washing.

D．isolate the child with impetigo from other members of the family.

某公司20×7年度与应收账款周转天数计算相关的资料为：年度营业收入为6000万元，年初应收账款余额为300万元，年末应收账款余额为500万元，坏账准备数额较大，按应收账款余额10%提取。假设每年按360天计算，则该公司应收账款周转天数为( )。

A．15
B．17
C．22
D．24