An office supply catalog gives a description of bookshelves that includes the following variables. Which of these variables is categorical? The width of a bookshelf in inches The width of a bookshelf in feet The weight of a bookshelf The color of the bookshelf The height of a bookshelf in inches

Categorical variables can assume values from a range of possible options, whereas quantitative variables can assume possibly infinitely many values from a certain number range.

So, the answer is "the colour of the bookshelf", because there can only be a limited number of possible colours for the bookshelf, whereas its width (no matter the unit measure) and height could be any number.