6313. Speaking in a tremulous tone, he took everybody to task.

✅ The correct answer is option D.
Confident : feeling or showing confidence in oneself or one’s abilities or qualities.

Angry : feeling or showing strong annoyance, displeasure, or hostility; full of anger.

Feeble : lacking physical strength, especially as a result of age or illness.

Trembling : shaking or quivering, typically as a result of anxiety, excitement, or frailty.

Tremulous : shaking or quivering slightly.

Synonym of Tremulous is Trembling