**Core Concept**
Viviparity refers to the mode of reproduction in which the developing young receives its nourishment from the mother's body and is born alive. This process is in contrast to oviparity, where the eggs are laid outside the mother's body and hatch externally.

**Why the Correct Answer is Right**
The term viviparous specifically describes organisms that give birth to live young, such as mammals. In mammals, the developing fetus receives its nourishment from the mother through a placenta, which is a complex organ that provides oxygen, nutrients, and waste removal. This process allows for the development of complex organs and systems in the fetus, enabling it to be born alive and thrive after birth.

**Why Each Wrong Option is Incorrect**
**Option A:** Oviparous organisms, such as birds and reptiles, lay eggs outside the mother's body and do not give birth to live young.
**Option B:**
**Option C:**
**Option D:**

**Clinical Pearl / High-Yield Fact**
It is essential to note that viviparity is a characteristic of mammals, whereas oviparity is a characteristic of birds and reptiles. This distinction is crucial in understanding the reproductive biology of different species and their adaptations to their environments.

**Correct Answer:** C.