Answer:
The correct answer would be C, abdominal.
Explanation:
This is true because the pelvic cavity is protected by the pelvis, the cranial cavity is protected by the skull, the spinal cavity is protected by the skull as well as the vertebral column, and the thoracic cavity is protected by the rib cage. Leaving the abdomen the only body cavity not being protected by some sort of bone.
I hope this helps! :)
