Which of the following organs synthesize urea?

Liver synthesize urea.

• Ammonia is the nitrogenous waste product of the human body. With the aid of a few enzymes located in the liver, this ammonia is changed into urea.
• Urea gets easily dissolved in water and forms a component of urine in kidneys. Urea is a form that may be easily eliminated from the body. The kidneys remove the urea that the liver produces.
• Liver converts harmful substances entering the body and those produced inside the body into harmless substances. Synthesis of urea from ammonia is an example of this. Ammonia formed in tissues diffuses into the blood and blood transports it to the liver. In liver, ammonia combines with carbon dioxide and water to form urea.

Hence, option C is the correct answer.