## Core Concept
The development of drawing skills in children is an important milestone in assessing their fine motor skills and cognitive development. Drawing shapes, including a triangle, is a significant achievement that reflects a child's ability to understand and replicate geometric forms.

## Why the Correct Answer is Right
Drawing a triangle is a complex task that requires a certain level of fine motor control and cognitive understanding of shapes. Typically, children progress from drawing simple shapes like lines and circles to more complex shapes. The ability to draw a triangle usually emerges after the child has mastered drawing a square, as it requires understanding of angles and more precise motor control. According to developmental milestones, children are usually able to draw a triangle around the age of 5 years.

## Why Each Wrong Option is Incorrect
- **Option A:** Drawing a triangle at this age is too early given the developmental milestones.
- **Option B:** This option might seem plausible but is still early for the average child to consistently draw a triangle accurately.
- **Option D:** This age is generally considered late for a child to first achieve the skill of drawing a triangle.

## Clinical Pearl / High-Yield Fact
A useful clinical pearl is that the sequence of drawing shapes in children typically follows this order: vertical line, horizontal line, circle, square, and then triangle. This sequence can be remembered with the acronym "VHCS-T". Knowing these milestones helps in assessing the developmental progress of children.

**Correct Answer: C. 5 years.**