Which of the following measurement is relative to 1percentage of the width of the viewport?

The correct answer is A. vw.

vw is a viewport width unit, which means it is relative to the width of the viewport. A viewport is the area of a web page that is visible in the browser window. The width of the viewport can be changed by resizing the browser window or by using a different device with a different screen size.

The other options are not viewport width units. B. vmax is the maximum viewport width. C. vmin is the minimum viewport width. D. ch is a character width unit.

A character width unit is relative to the width of a character in the current font. The width of a character can vary depending on the font, the font size, and the browser settings.