Which change in the kh-w-f paradigm is due to jussive contraction?

Complete Conjugation of Khāfa–Yakhāfu: Hollow Wāw from the Samiʿa Class

• Khāʾif to khāʾifāt
• Yakhāfu to lam yakhaf
• Khawf to akhwāf
• Khāfa to khāʾif