Let $A$ be a $4 \times 3$ real matrix with rank $2$. Which one of the following statement is TRUE?
1. Rank of $A^{T} A$ is less than $2$.
2. Rank of $A^{T} A$ is equal to $2$.
3. Rank of $A^{T} A$ is greater than $2$.
4. Rank of $A^{T} A$ can be any number between $1$ and $3$.