A 10-day old baby has undergone a surgery to repair cleft upper lip "hare-lip". Cleft upper lip has resulted from the following in this case:

Answer options

1. Nonclosure of the second pharyngeal arch
2. Nonclosure of the third pharyngeal arch
3. Nonclosure of palatine tori of maxillary processes of the first pharyngeal arch
4. Nonclosure of frontal and maxillary processes of the first pharyngeal arch
5. Nonclosure of the maxillary and mandibular processes of the first pharyngeal arch