What is the verbal noun of inkasara?

Characteristics of Form VII (Infiʿāl): Intransitivity, Manifestation, Resulting Action, Equivalence, Root Restrictions and Independent Use

• تَكْسِيرٌ
• اِسْتِكْسَارٌ
• كَاسِرٌ
• اِنْكِسَارٌ