**Core Concept**
Hyperesthesia refers to an increased sensitivity to stimuli, often manifesting as pain or discomfort upon palpation. In the context of abdominal surgery, specific signs are used to assess the presence of gallbladder disease, particularly cholecystitis. These signs rely on the patient's response to palpation over the gallbladder region.

**Why the Correct Answer is Right**
Boa's sign, also known as Boas' sign, is a clinical indicator of gallbladder disease. It is characterized by hyperesthesia over the region of the 12th rib, which corresponds to the gallbladder's anatomical location. This sign is observed when the patient experiences pain or tenderness upon palpation over this area, indicating inflammation of the gallbladder. The pathophysiology behind Boa's sign is related to the referred pain mechanism, where irritation of the diaphragm or the gallbladder causes pain to be referred to the 12th rib region.

**Why Each Wrong Option is Incorrect**
**Option A:** Murphy's sign is a clinical indicator of gallbladder disease, but it is characterized by the patient's sudden cessation of inspiration upon palpation over the gallbladder region, not hyperesthesia.

**Option C:** Moynihan's sign is not a recognized clinical indicator of gallbladder disease.

**Option D:** Aaron's sign is not a valid term in the context of gallbladder disease.

**Clinical Pearl / High-Yield Fact**
When examining patients for gallbladder disease, it is essential to appreciate the various clinical signs, including Boa's sign, that can indicate inflammation of the gallbladder. These signs can aid in the diagnosis and guide further management.

**✓ Correct Answer: B. Boa's sign**