Option 1 -> Starts with "into a blockbuster film" which cannot begin a sentence without a subject.
Option 2 -> Breaks the logical flow by placing "the hearts of audiences" immediately after the novel, disconnecting related phrases.
Option 3 -> Begins with "gained worldwide acclaim" without establishing what gained acclaim (no subject).
Option 4 -> Creates proper structure: subject (the novel) + main verb (gained acclaim) + prepositional phrase (after its adaptation into...) + relative clause (that captured hearts).
Hence, Option 4: (C), (B), (D), (A) -> Forms the coherent sentence: "The novel which had been dismissed as unremarkable gained worldwide acclaim after its adaptation into a blockbuster film that captured the hearts of audiences across generations." This follows proper syntax with clear subject-verb agreement and logical progression of ideas. -> correct