The soft drink brand Dr. Pepper is facing controversial with its ‘March of Progress’ ad campaign.  The company unveiled the ad on Facebook Sept. 13. The ad shows a chimpanzee dragging his knuckles, followed by a semi-erect figure reaching for a Dr. Pepper, which is then followed by a fully erect man walking and enjoying the beverage. The images are respectively captioned by “Pre-Pepper,” “Pepper Discovery,” and “Post-Pepper.”