Which of the following is a guideline you should follow when constructing pie charts?

A) Position the smallest slice or the slice that needs less emphasis at the 12 o'clock position.
B) Avoid labeling all the slices.
C) While labeling the slices, exclude information about the quantitative size, such as percentage, dollars, of each slice.
D) A legend should be used if it is not possible to place the appropriate labeling information beside each slice.

A legend should be used if it is not possible to place the appropriate labeling information beside each slice. This ensures that the reader knows exactly what each slice represents without cluttering the chart with too much labeling. Option A is not always necessary as the smallest slice may not always need less emphasis. Option B is not recommended as all the slices should be labeled for clarity. Option C is incorrect as quantitative size is important information to include when labeling slices.