A good tool to use when planning a comparison/contrast essay is

a. a transitional list.

b. an outline.

c. a Venn diagram.

d. a note card.

A good tool to use when planning a comparison or contrast essay is the use of a Venn diagram. The correct answer is option C. A Venn diagram uses two overlapping circles creating three sections, wherein it clearly illustrates the comparison and contrast of a certain topic. The side parts of both circles show the contrast or differences, and the middle part, where the circle overlaps, shows the similarities.