The Rule of Thirds Is

The Rule of Thirds is?

A) A composition guide that encourages placing important information at the intersection(s) of lines, if the frame is divided into thirds vertically and horizontally
B) A rule of thumb that you should check your images on the review screen every third picture to check for quality
C) The focal length of the lens should be one-third the shutter speed's bottom number of the fraction
D) The camera should never be placed at the bottom-third or top-third of the subject to be photographed