Otocephaly is a developmental disorder of:

 # Otocephaly is a developmental disorder of:

 A. Zygoma

B. Jaw bone

C. Occipital bone

D. Parietal bone

The correct answer is B. Jaw bone.

Otocephaly, also known as agnathia–otocephaly complex, is a very rare and lethal cephalic disorder characterized by the absence of the mandible (agnathia), with the ears fused together just below the chin (synotia). It is caused by a disruption to the development of the first branchial arch. It occurs in every 1 in 70,000 embryos.  

Reference: WIKIPEDIA