In What Way Does Perceptual Mapping Help the Marketer

In what way does perceptual mapping help the marketer?

A) Understanding the similarities and dissimilarities between competing product/services
B) Positioning or repositioning a product in the market place
C) Understanding how competing product/services are perceived by the target markets in terms of strengths and weaknesses
D) Tracking the progress of a marketing campaign on the perceptions of the target markets
E) All of the above