**Core Concept**
Albumin is a major plasma protein that plays a crucial role in maintaining blood volume, transporting hormones, and binding various substances. The half-life of albumin is an essential parameter in understanding its turnover and metabolism in the body.

**Why the Correct Answer is Right**
The half-life of albumin is approximately 20 days. This is because albumin is synthesized in the liver at a rate that is balanced by its degradation, primarily in the liver and kidneys. The normal half-life of albumin allows it to maintain a relatively stable concentration in the plasma, which is essential for its functions. The liver is the primary site of albumin synthesis, where it is produced by hepatocytes.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the half-life of albumin is not 5 days. A half-life of 5 days would imply a much faster turnover of albumin than what is actually observed in the body.
**Option B:** This option is incorrect because the half-life of albumin is not 10 hours. A half-life of 10 hours would imply an extremely rapid turnover of albumin, which is not consistent with its known physiological functions.

**Clinical Pearl / High-Yield Fact**
The half-life of albumin is an important parameter in clinical settings, particularly in patients with liver or kidney disease, where albumin metabolism may be altered. It is essential to understand the normal half-life of albumin to interpret laboratory results and make informed clinical decisions.

**Correct Answer: C. 20 days**