患者，王某，男性，因外伤导致尿失禁，现遵医嘱为该患者进行留置导尿。

为防止泌尿系统逆行感染，留置导尿管应

A．每日更换

B．每3天更换

C．每周更换

D．每2周更换

E．每3周更换

One year ago, an investor made five separate investments with the invested amounts and returns shown below. What is the arithmetic and geometric mean return on all of the investor's investments（）

A．15.79%

B．2.3%

C．10.79%