Tableau Desktop Foundations Practice Question

The correct answer is to drag the 'Quantity' measure to the 'Size' property on the Marks card. When a measure is placed on 'Size', Tableau uses the values of that measure to determine the size of each mark, making larger values correspond to larger marks and smaller values to smaller marks.

Dragging the measure to 'Color' would encode the data using a color gradient, not size. Dragging the measure to 'Detail' would increase the level of detail in the view but would not affect the size of the marks. Using the slider on the 'Size' property adjusts the size of all marks uniformly and does not tie the size to a specific measure's values.