Which of the following side effects is characterized by abnormal movements in the lips, tongue, and jaw?

Tardive dyskinesia is the correct answer because it specifically refers to a set of involuntary movements that can occur as a side effect of long-term use of antipsychotic medications. This condition is characterized by abnormal, repetitive movements that primarily affect the face, lips, tongue, and jaw. Patients may display symptoms such as lip smacking, tongue thrusting, and facial grimacing. These movements are often irreversible and develop after prolonged treatment with certain medications, especially first-generation antipsychotics.

In contrast, agranulocytosis is a serious side effect associated with a reduction in white blood cells, which increases the risk of infection and is not characterized by abnormal movements. Neuroleptic malignant syndrome is a potentially life-threatening condition associated with muscle rigidity, fever, and autonomic instability, rather than abnormal movements localized to the lips, tongue, and jaw. Akathisia involves a feeling of inner restlessness and the urge to move, leading to an inability to remain still, which does not specifically involve abnormal movements of the mouth or face. Thus, the specific involuntary movements seen in tardive dyskinesia make it the appropriate choice in this context.