Which of the following best describes the differences between propaganda and bias?

a. propaganda is used by organizations that are speaking truthfully, whereas biased articles may be true or false.
b. propaganda is intended to be persuasive, while bias expresses preference but is not necessarily persuasive.
c. the press can legally print biased articles, but they are not legally allowed to publish propaganda.
d. biased articles are typically negative, while propaganda tends to be positive.