## Core Concept
Language development milestones are crucial in pediatric assessment. The ability to put words together is a significant indicator of linguistic and cognitive development. Typically, children start combining words into short sentences around a specific age.

## Why the Correct Answer is Right
The correct answer, , corresponds with the developmental milestone where a child starts to put three words together to form a short sentence. This usually happens around 2 years of age. At this stage, children's vocabulary expands rapidly, and they begin to use short sentences to communicate. This developmental milestone is closely monitored by pediatricians as it reflects both cognitive and linguistic development.

## Why Each Wrong Option is Incorrect
* **Option A:** This age is too early for a child to consistently put three words together. At this age, children are just beginning to say their first words or have a very limited vocabulary.
* **Option B:** This is also too early for the milestone of putting three words together. Children at this age might start combining two words but not consistently forming three-word sentences.
* **Option D:** This age is later than when the milestone of putting three words together is typically achieved. By this age, children's language skills have advanced significantly, and they are likely forming more complex sentences.

## Clinical Pearl / High-Yield Fact
A key point to remember is that by 2 years of age, children are expected to put two to three words together to form simple sentences. This is a critical milestone, and significant delays may indicate the need for further evaluation for conditions such as language delay or developmental disorders.

**Correct Answer: C. 2 years.**