Option 1 -> Arduous means requiring strenuous effort, typically describing physically demanding tasks or laborious work, not complex arguments.
Option 2 -> Convoluted means extremely complex and difficult to follow, specifically describing intricate or twisted arguments and explanations.
Option 3 -> Gruelling means extremely tiring and demanding, usually referring to exhausting physical or mental ordeals, not complexity of logic.
Option 4 -> Traumatic means emotionally distressing or psychologically disturbing, relating to emotional harm rather than intellectual complexity.
Hence, Option 2: Convoluted -> This adjective perfectly captures a speech with a complex, intricate line of argument that is hard to follow due to its twisted or elaborate nature, which is exactly what the question describes -> correct