To rotate a point counterclockwise by 90 degrees, you can use the transformation:
\[ (x, y) \rightarrow (-y, x) \]
Given the point \( A(2, 4) \):
- Substitute \( x = 2 \) and \( y = 4 \) into the transformation: \[ (2, 4) \rightarrow (-4, 2) \]
Therefore, the new point after rotating \( A(2, 4) \) 90 degrees counterclockwise is \( (-4, 2) \).
The correct answer is: (−4, 2).