A school-age child is admitted to the hospital with a diagnosis of acute lymphoblastic leukemia. The nurse formulates a nursing diagnosis of Risk for infection. Which of the following is the most effective way for the nurse to reduce the child’s risk of infection<（）

A. Implementing reverse isolation.

B. Maintaining standard precautions.

C. Requiring staff and visitors to wear masks.

D. Practicing thorough hand washing.

简述SA8000标准主要内容。