(A) "break up" (III) → A couple ending their relationship due to irreconcilable differences uses "break up" which means to end a romantic relationship.
(B) "break through" (I) → Scientists overcoming barriers uses "break through" which means to overcome obstacles or make a significant advance.
(C) "break out" (IV) → Panic suddenly starting in a town uses "break out" which means to suddenly begin or erupt (used for panic, war, fire, etc.).
(D) "broke down" (II) → A car stopping functioning uses "broke down" which means to stop working due to mechanical failure.
Hence, Option 1: (A) - (III), (B) - (I), (C) - (IV), (D) - (II) → All four phrasal verbs are correctly matched with their contextual meanings: couples break up relationships, scientists break through barriers, panic breaks out suddenly, and vehicles break down mechanically → correct