The correct answer is C. steadfast.
Capricious means changing one’s mind frequently and without reason. Steadfast means firm in purpose or belief; not easily changed.
A. satisfied means feeling or showing pleasure or contentment. This is not the opposite of capricious, because someone who is satisfied could still change their mind frequently.
B. scattered means spread out over a wide area. This is not the opposite of capricious, because someone who is scattered could still change their mind frequently.
D. insured means protected by insurance against loss or damage. This is not the opposite of capricious, because someone who is insured could still change their mind frequently.