**Core Concept:**
Oxytocin is a peptide hormone involved in various physiological processes, including labor and childbirth, lactation, and social bonding. Its half-life is the time it takes for the concentration of the drug to decrease by half after administration. In pharmacology, the half-life helps understand how quickly a drug is eliminated from the body.

**Why the Correct Answer is Right:**
The correct answer is **D** (Mean half-life of oxytocin is approximately 6 minutes). Oxytocin has a relatively short half-life due to its rapid degradation by enzymes in the bloodstream. The drug is eliminated from the body through renal filtration and enzymatic degradation.

**Why Each Wrong Option is Incorrect:**

A. **Oxytocin's half-life is not 30 minutes.** The wrong option suggests a much longer half-life than the correct answer. This is incorrect because oxytocin rapidly degrades after administration, reflecting its short half-life.

B. **Oxytocin's half-life is not 1.5 minutes.** This option is incorrect as well, as it is shorter than the correct answer but still fails to capture the actual half-life of oxytocin.

C. **Oxytocin's half-life is not 4 hours.** This option is also incorrect because oxytocin's half-life is significantly shorter than 4 hours, making it unsuitable as an answer.

**Clinical Pearl:**
The short half-life of oxytocin highlights the need for frequent administration during labor and delivery to maintain adequate uterine contraction and ensure a safe delivery process. Oxytocin doses are typically administered every 5-10 minutes or less depending on the clinical situation, as its effects are transient and need regular replenishment. Understanding the pharmacokinetics of oxytocin helps clinicians manage the drug effectively during labor and childbirth.