Correct Answer: calm

Solution : The third option is the correct answer.

Tranquil describes a state of peace, quietness, and calmness. It suggests a serene and undisturbed atmosphere. Similarly, calm refers to a state of tranquillity and the absence of disturbance.

The meanings of the other options are as follows:

• Nervous means characterised by anxiety or unease, the opposite of tranquilly.
• Agitated refers to a state of nervousness or restlessness, indicating the opposite of calmness.
• Wild means characterised by a lack of restraint or control, often associated with chaos or disorder.

Therefore, the correct answer is calm.