Answer:
B. Excretory system
Step-by-step explanation:
Because the excretory system is made to remove urine which consists of waste materials such as excess salts and water. The kidneys are present in it as well. If there is too much water in the body the excretory system will produce urine with higher water concentration so whiteish urine will be produced and if there is a low amount of water in the body the excretory system will produce urine with lower water concentration so yelloish or greenish urine will be produced