**Core Concept**
The height of a newborn doubles approximately at a certain age, marking significant growth milestones. This phenomenon is closely related to the physical growth and development of infants, influenced by factors such as genetics, nutrition, and overall health.

**Why the Correct Answer is Right**
The height of a newborn typically doubles by 4-5 months of age. This rapid growth is largely due to the increase in length and weight of the infant, which is a reflection of the maturation of various bodily systems, including the musculoskeletal, circulatory, and nervous systems. As the infant grows, the skeletal system expands, and the muscles become stronger, enabling the child to support their increasing body weight and move around.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it is too early for the height of a newborn to double, considering the average growth rate during the first few months of life.

**Option B:** This option is incorrect as it is too late for the height of a newborn to double, given the average growth rate during the first few months of life.

**Option C:** This option is incorrect as it is not a commonly accepted age for the height of a newborn to double.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the growth rate of infants varies significantly, and a child's growth pattern should be closely monitored by pediatricians to identify any potential health concerns.

**Correct Answer:** C. 4-5 months.