For the past eight months, Sipho, a 9-year-old boy, has been in the principal’s office repeatedly due to his problematic behaviour. His teacher describes him as an angry little boy who is extremely argumentative, often showing vindictive and annoying behaviour and then blaming his peers for his own actions. He has even, on occasion, been cheeky and refused to do what the principal told him to do, to make amends with both his teacher and peers. Eventually, the principal referred Sipho to a psychologist for an assessment and intervention for his problematic behaviour. If the psychologist, after conducting a full assessment, were to diagnose Sipho’s abnormal behaviour according to the DSM-5-TR classification system, the diagnosis would most likely be - - - - -.