The correct answer is option (A):
Active
The correct answer is "Active".
The word "Quiescent" means in a state of inactivity or dormancy; at rest. To find the antonym, we need a word that describes the opposite state - being active and in motion.
* "Active" directly contrasts with "quiescent" as it means engaged in action or doing things.
Let's look at why the other options are incorrect:
* "Dormant" means in a state of temporary inactivity, similar to "quiescent." It is a synonym, not an antonym.
* "Nonchalant" means feeling or appearing casually calm and relaxed; not displaying anxiety, interest, or enthusiasm. This is unrelated to the concept of activity versus inactivity.
* "Weak" implies a lack of physical strength or power. While inactivity can sometimes be associated with weakness, it's not the direct opposite.
* "Aberrant" means departing from an accepted standard or a usual course. This describes something that deviates from the norm, not its level of activity.