Which best describes a likely result for the excretory system if the kidneys are weakened?

A.
Blood would not be filtered correctly and blood and waste would be excreted.

B.
Blood would not be filtered correctly and urine would back flow into the body.

C.
Blood would not be filtered correctly and the volume of urine would greatly increase.

D.
Blood would not be filtered correctly and waste materials will circulate in the blood instead of being excreted.