At a minimum, what does a Tableau associate need to create a simple scatter plot?

A basic scatter plot requires one measure on Columns and another measure on Rows, so D is correct. A scatter plot displays the relationship between two quantitative variables. One measure determines the horizontal position of each mark, while the second measure determines its vertical position. For example, placing SUM(Sales) on Columns and SUM(Profit) on Rows establishes a two-dimensional quantitative coordinate system. A dimension may then be added to Detail, Color, Shape, or another Marks property to create separate marks for entities such as customers, products, or states. However, that additional dimension is not the fundamental axis requirement identified by the question. The minimum structural requirement is two quantitative measures defining the x- and y-axes. A dimension plus a measure normally produces a categorical view such as a bar chart rather than a scatter plot. Two dimensions likewise do not supply the pair of quantitative scales required to analyze numerical correlation or distribution. Tableau's visual construction model distinguishes continuous quantitative measures, which generate axes, from discrete fields, which generally create headers. A scatter plot relies on two quantitative axes and therefore requires measures on both Rows and Columns. This is consistent with Tableau's standard scatter-plot construction methodology and its continuous-field behavior.