**Core Concept**
Iron metabolism involves the transport and regulation of iron in the body. One key glycoprotein plays a crucial role in this process by binding to iron and facilitating its transport in plasma. This glycoprotein is essential for maintaining iron homeostasis and preventing iron toxicity.

**Why the Correct Answer is Right**
The correct answer is **Transferrin**. Transferrin is a glycoprotein that binds to iron and forms a stable complex, which is then transported in plasma to various tissues and cells. This process is mediated by the transferrin receptor, which recognizes and binds to the transferrin-iron complex. Once inside the cell, the iron is released from transferrin and utilized for various cellular processes. Transferrin also plays a role in the storage and regulation of iron in the body.

**Why Each Wrong Option is Incorrect**
**Option A:** Ferritin is a protein that stores iron in a non-toxic form, but it is not a glycoprotein transported in plasma.

**Option B:** Ceruloplasmin is a copper-containing enzyme that plays a role in iron metabolism, but it is not the correct answer.

**Option C:** Haptoglobin is a protein that binds to free hemoglobin in plasma, but it is not involved in iron transport.

**Clinical Pearl / High-Yield Fact**
Remember that transferrin is a key player in iron metabolism, and its levels can be used as an indicator of iron status. Low transferrin levels can indicate iron deficiency, while high levels can indicate iron overload.

**Correct Answer:** C. Transferrin.