Final answer:
The most common rapidly developing tumor of the kidney that is most common in children is: 3) Wilms tumor.
Step-by-step explanation:
The most common rapidly developing tumor of the kidney that is frequently found in children is Wilms tumor, also known as nephroblastoma. Despite the other listed options being types of kidney tumors, Wilms tumor is specifically associated with children and is relatively rare in adults. It is important for it to be detected early as it can be quite aggressive, but it is also highly treatable with a good prognosis when treated promptly.
Treatment for Wilms tumor typically includes surgery and may also involve chemotherapy and/or radiation therapy, depending on the stage of the tumor. It is essential to be aware of the signs and symptoms of this condition in young children, which can include a noticeable swelling or lump in the abdomen, pain, nausea, or loss of appetite, among others. Early detection and treatment can significantly improve outcomes for affected children. The answer is option 3.