**Core Concept**
The zona pellucida is a glycoprotein layer surrounding mammalian oocytes (egg cells). It plays a crucial role in fertilization and gamete interaction. The zona pellucida is secreted by the oocyte during oogenesis and is composed of three glycoproteins: ZP1, ZP2, and ZP3.

**Why the Correct Answer is Right**
The zona pellucida acts as a barrier between the oocyte and the surrounding environment, regulating the entry of sperm cells. It binds to sperm via specific receptors, facilitating sperm binding and acrosome reaction. The zona pellucida is also involved in the selection of sperm, with only a subset of sperm capable of penetrating the zona pellucida and fertilizing the oocyte. This process is essential for successful fertilization and embryonic development.

**Why Each Wrong Option is Incorrect**
**Option A:** The zona pellucida is not responsible for providing nutrients to the oocyte.
**Option B:** The zona pellucida is not a component of the plasma membrane.
**Option C:** The zona pellucida is not involved in the regulation of oocyte maturation.

**Clinical Pearl / High-Yield Fact**
The zona pellucida is a critical structure in assisted reproductive technologies (ART) such as in vitro fertilization (IVF). The zona pellucida can be artificially removed or modified to facilitate fertilization in cases of infertility.

**Correct Answer: C. It acts as a barrier between the oocyte and the surrounding environment, regulating the entry of sperm cells.**