Why does a bold black word attract attention on white paper?

Correct answer: Because of dark and light contrast

The governing concept is contrast, especially value contrast between dark and light. A bold black word differs strongly from the white paper in tone and weight, so its edges are easy to see and the eye notices it quickly. Hence option A is correct. The paper’s thickness and the word’s lack of meaning do not create this visual effect, while similarity would make the word blend in rather than stand out.