6276. He was reasonable enough to behave according to the circumstances.

✅ The correct answer is option C.
Peaceful : free from disturbance; tranquil.

Attentive : paying close attention to something.

Sensible : (of a person) possessing or displaying prudence.

Determined : having made a firm decision and being resolved not to change it.

Reasonable : having sound judgement; fair and sensible.

Synonym of Reasonable is Sensible