Explanation
Correct answer: B.
Choice B is the best answer. Subject-modifier placement requires a modifier and its subject to be next to each other. The subject of the modifier "a coming-of-age story…colonialism" is Chraïbi’s novel The Simple Past, so the subject "Chraïbi’s debut novel" fits perfectly after this introductory modifying phrase.
Why the other choices are wrong
Choice A
Choice A is incorrect. Modifiers and their subjects must go next to each other. The introductory modifier "a coming-of-age story…colonialism" is describing Chraïbi’s novel, not Morocco. However, this choice places Morocco directly next to that modifier.
Choice C
Choice C is incorrect. Modifiers and their subjects must go next to each other. The introductory modifier "a coming-of-age story…colonialism" all describes Chraïbi’s novel, not Chraïbi himself. However, this choice places Chraïbi directly next to that modifier.
Choice D
Choice D is incorrect. Modifiers and their subjects must go next to each other. The modifier "a coming-of-age story…" is describing Chraïbi’s novel, so that needs to be the subject immediately after the modifier. This choice adds another modifier that describes Chraïbi’s novel, but then puts "Chraïbi" himself—not the novel—right after that modifier, which doesn’t make sense. Chraïbi wasn’t "published two years before" Moroccan independence; his novel The Simple Past was.