Option 1: Serene -> means calm and peaceful, which is similar to stoic, not opposite.
Option 2: Complaining -> means expressing dissatisfaction or annoyance, directly opposite to stoic behavior of enduring without complaint.
Option 3: Resigned -> means accepting something unpleasant, which aligns with stoic attitudes.
Option 4: Stolid -> means calm and unemotional, essentially a synonym of stoic.
Hence, Option 2: Complaining -> A stoic person endures hardship without showing emotion or expressing grievances, while a complaining person actively expresses dissatisfaction and discontent -> correct