The correct answer is: D. none of the mentioned
The viewport-width property sets the width of the viewport, which is the visible area of the page. The height property sets the height of the viewport. The @viewport rule is a CSS at-rule that allows you to specify properties for the viewport. However, there is no property that sets the viewport height in the same way as the width property.
The viewport-width property is a CSS property that sets the width of the viewport. The viewport is the visible area of the page, and it is typically determined by the size of the browser window. The viewport-width property can be used to set the width of the viewport to a specific value, or it can be used to set the width of the viewport to the width of the browser window.
The height property is a CSS property that sets the height of the viewport. The viewport is the visible area of the page, and it is typically determined by the size of the browser window. The height property can be used to set the height of the viewport to a specific value, or it can be used to set the height of the viewport to the height of the browser window.
The @viewport rule is a CSS at-rule that allows you to specify properties for the viewport. The viewport is the visible area of the page, and it is typically determined by the size of the browser window. The @viewport rule can be used to set the width and height of the viewport, as well as other properties such as the initial scale and the user-scalable property.
However, there is no property that sets the viewport height in the same way as the width property.