Final answer:
The evidence that best supports the claim is the manipulation of the truth in blaming the windmill's destruction on thin walls.
Step-by-step explanation:
The evidence that best supports the claim that Napoleon and Squealer's use of propaganda and manipulation is effective is the statement: "Out of spite, the human beings pretended not to believe that it was Snowball who had destroyed the windmill: they said that it had fallen down because the walls were too thin. The animals knew that this was not the case." This example shows how Napoleon and Squealer successfully manipulate the truth to their advantage by spreading false information.
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