**Core Concept**
The sequence of pubertal development in girls follows a well-defined, predictable pattern governed by hormonal changes, with theadlarche (breast development) being the first visible sign, followed by pubarche (pubic hair), linear growth spurt, and finally menarche (first menstrual period).

**Why the Correct Answer is Right**
Thelarche occurs first, typically between ages 8–13, marking the onset of breast development due to rising estrogen levels. This is followed by pubarche (pubic hair growth), which appears shortly after. A significant linear growth spurt occurs during early puberty, driven by growth hormone and sex steroids. Menarche, the first menstrual period, usually follows this sequence, typically around age 12–14, and marks the completion of pubertal development.

**Why Each Wrong Option is Incorrect**
Option B: Pubarche occurs after thelarche, not before — it is not the first sign of puberty.
Option C: Menarche cannot precede thelarche or pubarche, as hormonal changes required for menstruation are not present until later stages.
Option D: Menarche is the last event in the sequence, not the first — it cannot occur before breast or pubic hair development.

**Clinical Pearl / High-Yield Fact**
Remember the mnemonic: **"T-P-M-L"** – Thelarche, Pubarche, Menarche, Linear growth spurt. This sequence is consistent in girls and is used in clinical assessment of pubertal development.

✓ Correct Answer: A. Thelarche, Pubarche, linear growth spurt, Menarche