True statement regarding the kidney is?
A. Clearance will be more than GFR if the substance is secreted into the tubule
B. Descending limb is permeable to solutes
C. Fluid coming from the descending limb is hypotonic
D. Clearance of a substance is always more than GFR if there is tubular secretion
Please contribute to the discussion by posting the answer with references and pointing out any errors in the question!