Answer:
- Many mobile devices cannot display various fonts.
 - Mobile devices cannot access anything Flash-based.
 - Many mobile devices cannot access certain videos.
 
These are the three limitations to keep in mind when designing mobile websites. Many mobile devices cannot display certain fonts or access Flash-based content, and certain videos may not be accessible on some mobile devices. However, modern mobile devices can generally access content with JavaScript and PDF files, so A and B are not limitations to be kept in mind concerning mobile websites.