Which example supplies suitable reinforcement for a hesitant hearer?

Aḍrub al-Khabar: Ibtidāʾī, Ṭalabī and Inkārī Reports

• أَخُوكَ قَادِمٌ
• هَلْ أَخُوكَ قَادِمٌ؟
• إِنَّ أَخَاكَ قَادِمٌ
• لَا تَأْتِ