**Core Concept**
The talus bone in the ankle joint requires additional support from ligaments to maintain its position and facilitate smooth movement. The ligaments surrounding the talus play a crucial role in ankle stability and joint mobility.

**Why the Correct Answer is Right**
The correct ligament supporting the talus is the Deltoid ligament, also known as the medial ligamentous complex. It consists of a set of ligaments that provide medial (inner) support to the talus and the medial malleolus of the tibia. The Deltoid ligament is a vital structure that helps maintain the medial stability of the ankle joint, preventing excessive inversion and potential ankle sprains.

**Why Each Wrong Option is Incorrect**
* **Option A:** The **Anterior Talofibular Ligament (ATFL)** is actually a ligament that supports the lateral (outer) aspect of the ankle joint, not the medial aspect. It is commonly involved in lateral ankle sprains.
* **Option B:** The **Posterior Talofibular Ligament (PTFL)** is another ligament that supports the lateral aspect of the ankle joint, similar to the ATFL. It is also involved in lateral ankle sprains.
* **Option D:** The **Calcaneofibular Ligament (CFL)** is a ligament that supports the lateral aspect of the ankle joint, connecting the calcaneus and fibula bones. It is also involved in lateral ankle sprains.

**Clinical Pearl / High-Yield Fact**
The Deltoid ligament is often injured in high-impact injuries, such as falls from a height or motor vehicle accidents, leading to medial ankle instability and chronic pain.

**Correct Answer:** D. Deltoid ligament.