If GFR is 125 ml/min, and you are studying a drug that has a renal clearance rate of 20 ml/min, you can conclude that

A. The drug is secreted

B. The drug is reabsorbed

C. The drug is neither secreted nor reabsorbed

(B). The drug is reabsorbed.

Explanation:

Renal clearance rate determines the excretion of drugs into the urine during excretion. It is used to study the main process associated with a drug's renal excretion.

When the renal clearance rate is lower than GFR (glomerulus filtration rate), the drug is absorbed in the renal tubules. When the renal clearance rate is higher than GFR, the drug is secreted into the urine. When the renal clearance rate is equal to the GFR, the drug is neither reabsorbed nor secreted.

As for given drug, renal clearance is 20 ml/min (less than GFR), this drug will reabsorbed.

Thus, the correct answer is option (B).