**Core Concept**
The half-life of oxytocin is a critical pharmacokinetic parameter that determines its duration of action when administered intravenously. Oxytocin is a peptide hormone with a relatively short half-life due to its rapid degradation by enzymes. Understanding the half-life of oxytocin is essential for managing postpartum hemorrhage and other obstetric conditions.

**Why the Correct Answer is Right**
The half-life of oxytocin is approximately 3-5 minutes when administered intravenously. This short half-life is due to the rapid degradation of oxytocin by oxytocinase, a metalloprotease enzyme found in plasma and tissues. As a result, repeated doses of oxytocin are often necessary to maintain its uterotonic effects.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it inaccurately represents the half-life of oxytocin.
**Option B:** This option is incorrect because it is significantly longer than the actual half-life of oxytocin.
**Option C:** This option is incorrect because it is shorter than the actual half-life of oxytocin.

**Clinical Pearl / High-Yield Fact**
When administering oxytocin for postpartum hemorrhage, it's essential to consider its short half-life and adjust the dosage regimen accordingly to maintain adequate uterotonic effects.

**Correct Answer: B. 3-5 minutes**