How is a contrast ratio calculated on a text?

Question

Accepted Answer

Contrast ratio between the color of the text and the color of its background, depending on the size and weight of the text

Answer

Contrast ratio between the color of the text and the color of its background

Answer

Contrast ratio between the color of the text and the color of its background, depending on the text size

Answer

Contrast ratio between the color of the text and the color of its background, according to the spacing of the text

Question from the Web Accessibility test