The answer is D. Tense.
The other four words (gloomy, calm, dull, and distress) all describe emotions. Tense, on the other hand, describes a state of physical or mental strain or tension.
- Gloomy describes a feeling of sadness or depression.
- Calm describes a feeling of peace and tranquility.
- Dull describes something that is not interesting or exciting.
- Distress describes a state of great anxiety or suffering.
