Hello friends, I took the SEO quiz at SEOMOZ and i want to know the explanation of one of the questions. I am posting the answer along with the question. Hoping for good explanation. Q) Which of the following is an acceptable way to show HTML text to search engines while creating a graphical image to display to users? a) User-agent based cloaking - show search engine agents text and browser agents the image b) CSS layers - show the text on a layer underneath the image atop c) IP-based Cloaking - show search engine IPs the text and other IPs the image d) CSS image replacement - create a rule in the CSS file that replaces the text with an image based on a given class The correct answer is 'd'