Which Arabic sentence means “Zayd has not written yet”?

لَنْ يَكْتُبَ زَيْدٌ
لَمَّا يَكْتُبْ زَيْدٌ
لَمْ يَكْتُبْ زَيْدٌ
يَكْتُبُ زَيْدٌ