**Core Concept:** Closure of sutures is an essential aspect of cranial development and growth, which can be broadly categorized into three stages:
1. **Neurogenesis:** The formation of neural cells and the development of the brain.
2. **Mesenchymal Invasion:** The migration of mesenchymal cells to the suture area.
3. **Sutural Apposition:** The union of the involved bone plates.

**Why the Correct Answer is Right:**
The spheno-occipital suture is a complex suture that begins its closure in early childhood and is almost entirely fused by late adolescence. It is a crucial process for the proper development of the skull and brain. In the correct answer, **C**, closure occurs in early childhood, which aligns with the typical age range for suture closure.

**Why Each Wrong Option is Incorrect:**
A. **False:** Closure occurs in early childhood, not during puberty.
B. **False:** Closure begins in early childhood, not during adulthood.
D. **False:** Closure starts in early childhood, not in adolescence.

**Clinical Pearl / High-Yield Fact:**
Understanding the timing of suture closure is essential for diagnosing various craniosynostosis syndromes, where premature fusion of sutures occurs, causing abnormal skull shape and potential developmental delays.

**Correct Answer: C. Early Childhood**