While all of these aspects are important to keep in mind when using a visual aid for a presentation (with he exception of option A), they do vary in importance. Option A is definitely not your answer because orators use graphic organizers and charts of many sorts to convey a message through their presentation. In order to do so, they often point at it or reference it in many ways.
In relation to the other three aspects mentioned, the most important one to keep in mind would be option C. As soon as the orator turns to read from a slide, they disconnect from their audience and hinder the effectiveness of their message. After that, option D would be the most important since it wouldn't matter if the aid is in full view or not if the audience can't read it.
