Final answer:
The first choice medication for managing the 9-year-old boy's condition of selective mutism is fluoxetine (Prozac), a selective serotonin reuptake inhibitor (SSRI). SSRIs help reduce anxiety and improve communication skills.
Step-by-step explanation:
The 9-year-old boy's symptoms, including refusing to talk in class and only using gestures, indicate a possible selective mutism, which is an anxiety disorder. The first choice medication for managing selective mutism is usually fluoxetine (Prozac), a selective serotonin reuptake inhibitor (SSRI). SSRIs like fluoxetine increase the levels of serotonin in the central nervous system, helping to reduce anxiety and improve communication skills.