Which synonym best describes a person who is not upset during a loud and angry discussion?

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Which synonym best describes a person who is not upset during a loud and angry discussion?

Gentle: lacking harshness or roughness

Quiet: not making noise

Restful: peaceful and quiet in a relaxing way

Unruffled: calm during times of confusion

Unruffled

Explanation:

While the other options do refer to a state of calmness, they don´t inherently provide any connection to a stressful situation such as an intense and impassioned argument.  

Only "Unruffled" implies that that state of tranquility happens in the middle of a surprising or frightening event.

Saying that someone remains unruffled, means that even under a stressful situation they don´t seem to be affected.

the anterior pituitary gland produces the following hormones and releases them into the bloodstream: psychotropic hormone, which stimulates the adrenal glands to secrete steroid hormones, principally cortisol. growth hormone, which regulates growth, metabolism and body       hope i