**Core Concept**
Bone growth during puberty is regulated by a complex interplay of hormonal and physiological factors. The growth hormone-insulin-like growth factor 1 (GH-IGF-1) axis plays a crucial role in regulating bone growth, while the sex steroids estrogen and testosterone modulate the growth process.

**Why the Correct Answer is Right**
The correct answer is growth hormone (GH) because it stimulates the liver and other tissues to produce IGF-1, which in turn stimulates the proliferation and differentiation of chondrocytes and osteoblasts, leading to bone growth. The GH-IGF-1 axis is essential for the regulation of bone growth during puberty, and any disruption in this axis can result in growth hormone deficiency or excess, leading to conditions such as dwarfism or acromegaly.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while growth hormone is essential for bone growth, it is not the only factor involved in regulating bone growth during puberty. Other hormones such as estrogen and testosterone also play a crucial role in modulating bone growth.

**Option B:** This option is incorrect because while IGF-1 is a key mediator of the growth hormone axis, it is not the primary regulator of bone growth during puberty.

**Option C:** This option is incorrect because while sex steroids such as estrogen and testosterone do play a role in regulating bone growth during puberty, they are not the primary regulators of bone growth.

**Clinical Pearl / High-Yield Fact**
A key clinical pearl to remember is that growth hormone deficiency or excess can result in significant morbidity, including short stature or acromegaly, and should be promptly diagnosed and treated.

**Correct Answer: D. Growth hormone**