In the word happy, the letter that exhibits order 2 rotational symmetry is h. This means that if you rotate the letter h by 180 degrees (or half a turn), it looks the same as it did before the rotation.
To further elaborate, order 2 symmetry allows an object to map onto itself in two orientations: the original position and after a half turn. When we visually examine the letter h, we can see that if you were to rotate it around its center point, it retains its appearance. In contrast, the other letters in the word ‘happy’ (a, p, y) do not exhibit this characteristic.