In mathematics, a horizontal reflection across the x-axis transforms a point \((x, y)\) to \((x, -y)\).
For the point \((-2, 1)\):
- The x-coordinate remains the same: \(-2\)
- The y-coordinate is negated, changing from \(1\) to \(-1\)
Thus, the reflection of the point \((-2, 1)\) will be:
\[ (-2, 1) \rightarrow (-2, -1) \]
Therefore, the correct response is:
"In the horizontal reflection, the point \((-2, 1)\) becomes \((-2, -1)\)."