Step 1: “Quiescent” refers to a state of being inactive or quiet, often used in biological or physical contexts.
Step 2: The opposite of “quiescent” would be “active,” referring to something that is engaging or functioning.
Step 3: “Dormant” refers to a state of inactivity or rest, but it is not the opposite of quiescent in the same active sense. “Weak” and “unconcerned” do not relate to the opposite of “quiescent.”
Thus, the correct answer is: “active.”