What may be the educational reason for placing primary colours at the top of a colour mixing chart?

Correct answer: They help explain the origin of the mixed colours below

The governing concept is that primary colours are treated as starting colours in the traditional subtractive colour model. A chart places them first so learners can trace results: red plus yellow produces orange, yellow plus blue produces green, and blue plus red produces violet. Thus option D correctly explains the cause-and-result structure; cost, darkness, and decoration do not explain the chart’s educational order.