The point P (-1,2) is rotated to become P′

To determine the rotation that maps point P (-1, 2) to point P' (2, 1), we can analyze the coordinates.

First, we can find the vector from P to P':
- Starting point P = (-1, 2)
- End point P' = (2, 1)

Calculating the vector:
Δx = 2 - (-1) = 3
Δy = 1 - 2 = -1

Next, we can think about the typical rotations:

- A **90° rotation** clockwise gives us a transformation from (x, y) to (y, -x).
- A **90° rotation** counterclockwise gives us (x, y) to (-y, x).
- A **180° rotation** transforms (x, y) to (-x, -y).
- A **−90° rotation** (or **270° rotation** clockwise) transforms (x, y) to (-y, x) (same as 90° counterclockwise).

To find out the rotation type:

1. **Starting with the 90° Clockwise Rotation**:
- From P (-1, 2): (2, 1) matches.

2. **Check the vector**: The initial vector is (3, -1), which corresponds to a movement down and right. This is a clockwise rotation.

Thus, the movement from P (-1, 2) to P' (2, 1) represents a **90° clockwise rotation**.

Therefore, the correct response is:

**90° rotation**.