Sentence 2 stands apart from the rest because it presents a broader notion concerning efforts to prohibit books and stifle authors, diverging from the specific focus of the other sentences on book banning and challenges within the US. Sentences 1, 3, 4, and 5 collectively construct a cohesive paragraph addressing the prohibition of Northern Lights and the increasing frequency of book challenges in the US. In contrast, Sentence 2 introduces a distinct perspective that doesn't directly enhance the narrative flow concerning the particular incidents and trends outlined in the other sentences.
So, the correct option is (B): Attempts to ban books are attempts to silence authors who have summoned immense courage in telling their stories.