"Giving a speech that spreads harmful lies about a private citizen" is an activity which is considered as slander.
Step-by-step explanation:
Slander basically means speaking untruth or any such thing in public or to someone in such a way that it harms the reputation of the person about whom one is talking. So as the meaning is clear, let's look at the options, printing an article, it is not slander, as slander is the untruth told to someone else.
Publishing a book is again not a slander. Statements about business criticising the government; well few people might think of the same as slander, but it is not slander, as if someone is criticising, he is only sharing his thoughts, however, he is not telling an untruth about anyone.