**Core Concept**
Albumin is a major protein produced by the liver, playing a crucial role in maintaining blood volume, transporting hormones and drugs, and regulating osmotic pressure. The half-life of albumin is an essential parameter that influences its pharmacokinetics and clinical applications.

**Why the Correct Answer is Right**
The half-life of albumin is approximately 20 days. This prolonged half-life allows albumin to remain in the circulation for an extended period, enabling it to perform its various functions effectively. The half-life of albumin is influenced by the liver's synthetic rate and the rate of its catabolism. Albumin is primarily degraded in the reticuloendothelial system, particularly in the liver and spleen.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as the half-life of albumin is not approximately 2 days. This value is more characteristic of other proteins, such as clotting factors.
**Option B:** This option is incorrect as the half-life of albumin is not approximately 5 days. This value may be seen in some acute or chronic diseases affecting albumin metabolism.
**Option C:** This option is incorrect as the half-life of albumin is not approximately 10 days. This value might be seen in some conditions affecting liver function or protein metabolism.

**Clinical Pearl / High-Yield Fact**
The prolonged half-life of albumin makes it an ideal carrier protein for drugs, such as warfarin and phenytoin, which are bound to albumin in the bloodstream. This binding affects their pharmacokinetics and clinical efficacy.

**Correct Answer: C. 20 days.**