A child is admitted with a suspected diagnosis of Wilms' tumor. The nurse should place a sign with which of the following warnings over the child's bed?

A. Collecting all urine may be relevant in certain conditions, such as kidney function monitoring, but it is not specific to Wilms' tumor management. B. Restrictions on venipuncture or blood pressure in a specific arm are relevant for conditions like lymphedema or post-mastectomy, not Wilms' tumor. C. Contact precautions are necessary for infectious diseases, not applicable to Wilms' tumor. D. Wilms' tumor is a renal tumor, and palpating the abdomen could potentially cause the tumor to rupture and spread malignant cells. Therefore, it is critical to avoid any abdominal palpation in these patients.