Which active form means “you women will certainly do”?

Emphatic Lām and the Heavy and Light Nūn Paradigms

• لَتَفْعَلُنَّ
• لَتَفْعَلَانِّ
• لَيَفْعَلْنَانِّ
• لَتَفْعَلْنَانِّ