**Core Concept:**
The question is asking about the stage in tooth development where the process of mineralization and root formation commence. This stage is crucial as it marks the transition from the formation of dental pulp to the formation of the tooth structure. The correct answer pertains to the maturation phase of tooth development.

**Why the Correct Answer is Right:**
In the maturation phase of tooth development, also known as the calcification phase, the enamel and dentin matrix are mineralized, leading to the formation of hard tooth structures. This process occurs primarily in the dental pulp, which is the soft tissue within the tooth responsible for mineralization. The dental pulp secretes a protein called dentin matrix protein (DMP), which is crucial for mineralization.

**Why Each Wrong Option is Incorrect:**
A. This option is incorrect because the formation of dental pulp and mineralization occur in the maturation phase, not in the early stages of tooth development.
B. This answer is incorrect because the early stages of tooth development involve the formation of dental lamina and the calcification of the enamel and dentin.
C. This option is incorrect because the initiation of mineralization and root formation actually occurs in the maturation phase, not in the calcification phase.
D. This answer is incorrect because the calcification phase focuses on mineralization of the enamel and dentin, not the maturation phase where root formation takes place.

**Clinical Pearl / High-Yield Fact:**
Understanding the stages of tooth development is crucial for dentists and oral surgeons, as it helps in diagnosing dental anomalies and guiding treatment interventions. Knowledge of the calcification phase, maturation phase, and the later stages of tooth development is essential for a comprehensive understanding of dentistry and oral health.

**Correct Answer:**
C. Maturation Phase

Explanation: The correct answer is the **maturation phase** because it marks the beginning of mineralization and root formation in tooth development. In this phase, the dental pulp initiates mineralization and root formation, which leads to the formation of hard tooth structures and the development of the tooth root.