Final answer:
Dexter would likely exhibit a lack of remorse over harming others, which is a symptom of antisocial personality disorder.
Step-by-step explanation:
Dexter has recently been diagnosed with antisocial personality disorder. Individuals with this disorder often exhibit behaviours such as a lack of remorse over harming others. Therefore, the most fitting symptom for Dexter would be A) Lack of remorse over harming others. This can include indifference or rationalization of having hurt, mistreated, or stolen from another person. The other options listed such as extreme sensitivity to social evaluation, debilitating fear of public speaking, and unwillingness to socialize with others are not typically associated with antisocial personality disorder but may relate to other mental health issues such as social anxiety disorder.