The branch of medical science that deals with kidneys is known as:

Nephrology

The correct answer is Option (4)-Nephrology

The branch of medical science that deals specifically with the study, diagnosis, and treatment of kidneys is known as Nephrology. Nephrologists are medical professionals who specialize in this field, focusing on kidney-related conditions and disorders. They play a crucial role in managing various kidney diseases, kidney transplantation, and addressing issues related to kidney function and health.