**Core Concept**
The glomerular filtration rate (GFR) is a measure of kidney function that represents the volume of fluid filtered from the renal glomerular capillaries into the Bowman's capsule per unit time. At rest, the GFR is maintained within a narrow range to ensure proper fluid balance and electrolyte homeostasis.

**Why the Correct Answer is Right**
The normal GFR in a resting person is approximately 125 milliliters per minute (mL/min) per 1.73 square meters of body surface area (BSA). This rate is determined by the glomerular filtration pressure, which is influenced by the renal perfusion pressure, glomerular hydrostatic pressure, and the oncotic pressure of the blood. The glomerular capillary bed is highly specialized to facilitate the filtration of small molecules, such as water, ions, and glucose, while retaining larger molecules, like proteins and blood cells.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not provide a numerical value, making it impossible to determine its accuracy.
* **Option B:** This option is incorrect because it suggests a GFR value that is significantly lower than the normal range, which would indicate impaired kidney function.
* **Option C:** This option is incorrect because it suggests a GFR value that is significantly higher than the normal range, which would indicate hyperfiltration.

**Clinical Pearl / High-Yield Fact**
A decrease in GFR is an early indicator of kidney damage or disease, and can be detected using the serum creatinine level or the estimated GFR (eGFR) formula. It's essential to recognize that a GFR below 60 mL/min/1.73 m^2 indicates chronic kidney disease (CKD) and requires prompt medical attention.

**Correct Answer:** C. 120.