To rotate a point \((x, y)\) about the origin by 270° (which is equivalent to a 90° clockwise rotation), you can use the following transformation:
\[ (x, y) \rightarrow (y, -x) \]
We need to apply this transformation to point B which has coordinates \((-2, 4)\).
Applying the transformation:
\[ (-2, 4) \rightarrow (4, -(-2)) = (4, 2) \]
Therefore, the coordinates of the image of point B after the triangle is rotated 270° about the origin are \((4, 2)\).
The correct answer is: \((4, 2)\)