Concept:The word "loud" here describes a person who is talkative, outgoing, or attention-seeking in behaviour.
Its opposite is a person who is quiet, restrained, or not open in expressing themselves.
Explanation:Among the options, "reserved" means quiet, shy, or unwilling to express feelings openly.
"Peaceful" means calm and free from disturbance, which is not the direct opposite here.
"Humble" means modest, and "respectful" means polite, neither of which contrasts with "loud" in behaviour.
Therefore, the best word to fill the gap is "reserved."
Answer:A. reserved