According to the fair use doctrine

A) plagiarism is not an issue in the business world—it is a problem only in schools and academic circles.
B) crediting sources is all that is necessary to avoid legal problems.
C) once material is made public, it no longer belongs to the author.
D) you can use other people's work only if you don't prevent them from benefiting as a result.
E) any information found in two or more places is considered public.

D
Explanation: D) For example, if you publish a cartoon without attribution that gets widely picked up by newspapers and other sources, you are preventing the cartoonist from benefiting—since the cartoonist could have sold the rights to the cartoon in each instance that it was picked up.