# Inverse of Absolute Value Function

**Algebra**Level 3

Consider the function \( f: [ -1, \infty) \rightarrow \mathbb{R} \), given by \(f(x)=|x+1|+1\).

Which of the following must be in the domain of the inverse function \(f^{-1}(x)\)?

**I**: \(-1\).

**II**: \(0\).

**III**: \(1\).

\[\] **Notation**: \( | \cdot | \) denotes the absolute value function.