**Core Concept**
Adrenarche refers to the increase in production of adrenal androgens, such as dehydroepiandrosterone sulfate (DHEA-S), by the adrenal glands during childhood. This process is crucial for the development of secondary sex characteristics in children, including pubic hair, acne, and body odor.

**Why the Correct Answer is Right**
Adrenarche typically starts around the age of 6-8 years in girls and 8-10 years in boys, as the adrenal glands begin to produce more DHEA-S. This increase in adrenal androgen production is triggered by the hypothalamic-pituitary-adrenal (HPA) axis, leading to the development of secondary sex characteristics. The production of DHEA-S also increases the levels of testosterone and estrogen in the body, contributing to the development of pubic hair, acne, and body odor.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because adrenarche typically starts after the onset of puberty, not before. While some girls may experience adrenarche as early as 6 years, it is not a universal occurrence.

**Option B:** This option is incorrect because the correct age range for the onset of adrenarche is between 6-10 years, not 12-14 years.

**Option C:** This option is incorrect because while some boys may experience adrenarche as early as 8 years, it is not a universal occurrence, and the correct age range is between 8-12 years.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the onset of adrenarche can vary among individuals, and not all children will exhibit the same signs and symptoms. A pediatrician or healthcare provider may use the Tanner stages to assess the development of secondary sex characteristics in children.

**Correct Answer:** C. 8-10 years.