In renal hemodynamics:
a) Inulin clearance rises with an increase in inulin plasma level
b) A substance that has a clearance less than that of inulin must be reabsorbed d by the tubules
c) Renal plasma flow is measured by clearance of creatinine
d) Urea clearance provides a close estimation of GFR
e) If the renal clearance of a substance exceeds that of inulin it must be secreted into the tubules