Final answer:
The organ that lies in the periumbilical region is the small and large intestines (option a).
Step-by-step explanation:
The organ that lies in the periumbilical region is the small and large intestines (option a).
In the periumbilical region, you can find the appendix and the cecum, which are part of the large intestine. The small intestine also lies in this region, although it extends beyond it. The bladder, liver, and stomach do not lie in the periumbilical region.