Which rule is illustrated by khabīthatin ijtuththat?

Meeting of Two Sākin Letters — ʿAlā Ḥaddih, Ghayr Ḥaddih and Tanwīn

• Madd before shaddah
• Plural mīm with ḍammah
• Tanwīn followed by hamzat al-waṣl
• Lām of Allāh