Option 1 -> Calm means stable and peaceful, opposite of unpredictable and changeable.
Option 2 -> Erratic means unpredictable and irregular, which is a synonym of volatile.
Option 3 -> Capricious means prone to sudden changes in mood, which is a synonym of volatile.
Option 4 -> Translucent refers to light passing through something, unrelated to volatile's meaning.
Hence, Option 1: Calm -> Volatile describes something unstable, unpredictable, and prone to rapid change, while calm represents stability and tranquility, making it the most appropriate antonym -> correct