(A) - (II) complacent → Self-satisfied person who stops making effort after initial success.
(B) - (IV) complaisant → Eager to please and willing to help others.
(C) - (I) coarse → Rough or harsh texture.
(D) - (III) course → A program or series of educational lessons.
Hence, Option 4: (A) - (II), (B) - (IV), (C) - (I), (D) - (III) → The homophones are correctly matched: "complacent" (self-satisfied) vs "complaisant" (eager to please), and "coarse" (rough texture) vs "course" (program of study). Each word fits its contextual meaning perfectly in the given sentences. → correct