Why Do the Textbook Authors State That Studying the Impact

Why do the textbook authors state that studying the impact of computers and television separately is no longer valuable?

A) Children generally spend media time playing games, and so these measures are no longer useful.
B) Television shows can be streamed through mobile computer devices, and computer games can be played on televisions, so the line between the two is blurred.
C) Computers play a minor role in the lives of young children.
D) Young users are drawn to user-friendly computer devices and away from television, so television measures are uninformative.