If you really thing about the urinary system as one big piece all of the above would be an answer but “C. They filter the blood, reabsorbing water and removing waste” would be the precise answer because they kidneys release urine through the uriters ( can’t spell ) all the way down to the bladder, witch stores and then down to the urithea to be rid of. As the urine was traveling, it was extremely filtered from the kidneys so the waste can be released.
