All the other male pigs on the farm were porkers. The
best known among them was a small fat pig named
Squealer, with very round cheeks, twinkling eyes, nimble
movements, and a shrill voice. He was a brilliant talker,
and when he was arguing some difficult point he had a
way of skipping from side to side and whisking his tail
which was somehow very persuasive. The others said of
Squealer that he could turn black into white.
-Animal Farm,
George Orwell
Which statement best explains the central idea from
the passage?
Squealer doesn't know the difference between right
and wrong.
Squealer uses body language to get his point
across.
Squealer can make others believe anything, even
lies.
Squealer's manner of presentation entertains
others.

Reading this passage carefully we can find some key descriptions of Squealer (persuasive, he could turn black into white). That means he is fully aware of the things he says and that he uses his gift for convincing people for his own gain.

Although he had a very characteristic appearance, his physique only enhance the effect of his words.

In the book Animal farm, Squealer works under the main leader Napoleon, his character is based on Vyacheslav Molotov who was Stalin's protégé and head of Communist propaganda. He uses his skills as an effective orator to manipulate the mass with a goal to direct them in a way which suits Napoleon.