(a) I think the image was altered so people would believe that the product actually works, and would therefore buy it. What makes it look altered is that although the camera is so close, the model has little to no visible pores on her face, which is impossible in reality.
(b) The target audience are gullible people with really crappy skin, and who want to look beautiful.
(c) The intention of this image is to make people think that this product will clear up your skin, and make you look purdy.
(d) This image was found on a web page that displays different Neutrogena ads.
http://kristink.fanwired.com/neutrogenaads.html
