Choose the answer that describes the hierarchy among these three body regions.
A. The oral region is part of the facial region, and the facial region is part of the cephalic region.
B. The cephalic region is part of the facial region, and the facial region is part of the oral region.
C. The cephalic region is part of the facial region, and the facial region is part of the manual region.
D. The oral region is part of the cephalic region, and the cephalic region is part of the facial region.