Concept:An antonym is a word with the opposite meaning. "Perturbed" means anxious, troubled, or unsettled.
Explanation:The word "perturbed" describes a state of mental disturbance or unease. To find its antonym, look for a word meaning peaceful and composed.
- Option A (Unsettled) is similar to perturbed, not opposite.
- Option B (Worried) also means anxious, so it is a synonym.
- Option C (Anxious) directly matches perturbed’s meaning.
- Option D (Calm) means free from agitation, the exact opposite. Thus, "calm" is the correct antonym.
Answer:Calm (Option D)