Option 1: (A)-(II), (B)-(III), (C)-(IV), (D)-(I) → Incorrectly matches "off the top of one's head" with remaining calm, which is wrong.
Option 2: (A)-(III), (B)-(IV), (C)-(I), (D)-(II) → Correctly pairs all idioms: spontaneous responses, disagreement, pretense, and composure.
Option 3: (A)-(II), (B)-(I), (C)-(IV), (D)-(III) → Incorrectly matches "take issue with" as pretending to agree, which is opposite.
Option 4: (A)-(IV), (B)-(III), (C)-(I), (D)-(II) → Incorrectly matches "off the top of one's head" with disagreement.
Hence, Option 2 → "Off the top of one's head" means speaking without careful thought (III), "take issue with" means to disagree (IV), "pay lip service to" means pretending to support something (I), and "keep one's head" means staying calm under pressure (II) → correct