**Core Concept**
Bartter's syndrome is a rare genetic disorder characterized by impaired salt reabsorption in the thick ascending limb of the loop of Henle in the kidneys. This leads to hypokalemia, metabolic alkalosis, and normal to low blood pressure.

**Why the Correct Answer is Right**
Type II Bartter's syndrome is associated with sensorineural deafness due to mutations in the BSND gene, which encodes the barttin protein. Barttin is a chloride channel accessory protein that is essential for the function of the Na-K-2Cl cotransporter in the thick ascending limb of the loop of Henle. The mutations in the BSND gene disrupt the function of barttin, leading to impaired salt reabsorption and sensorineural deafness.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Type I Bartter's syndrome is not associated with sensorineural deafness, but rather with mutations in the SLC12A1 gene that encodes the Na-K-2Cl cotransporter.
**Option B:** This option is incorrect because Type III Bartter's syndrome is associated with mutations in the CLCNKB gene that encodes the chloride channel, but it is not associated with sensorineural deafness.
**Option C:** This option is incorrect because Type IV Bartter's syndrome is associated with mutations in the KCNJ1 gene that encodes the potassium channel, but it is not associated with sensorineural deafness.

**Clinical Pearl / High-Yield Fact**
Bartter's syndrome is a rare genetic disorder that requires a high index of suspicion for diagnosis, as its presentation can be variable and nonspecific.

**Correct Answer: B. Type II Bartter's syndrome**