**Core Concept**
H2 blockers are a class of medications that reduce stomach acid production by inhibiting the action of histamine on the parietal cells in the stomach. They are commonly used to treat conditions such as duodenal ulcers, gastroesophageal reflux disease (GERD), and Zollinger-Ellison syndrome.

**Why the Correct Answer is Right**
H2 blockers are typically given for a short period of time to allow the ulcer to heal. The recommended treatment duration for duodenal ulcers with H2 blockers is usually 6-8 weeks. This duration is sufficient for the ulcer to heal, and it also helps to prevent complications such as bleeding or perforation. The use of H2 blockers for a longer duration can lead to rebound acid hypersecretion, which can worsen the condition.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because H2 blockers are not typically given for a prolonged period of time, as it can lead to rebound acid hypersecretion.
**Option B:** This option is incorrect because the recommended treatment duration for duodenal ulcers with H2 blockers is usually not longer than 8 weeks.
**Option D:** This option is incorrect because the treatment duration for duodenal ulcers with H2 blockers is not typically determined by the severity of the symptoms.

**Clinical Pearl / High-Yield Fact**
It is essential to note that H2 blockers should be used in conjunction with other treatments, such as antacids or proton pump inhibitors (PPIs), to provide optimal symptom relief and promote ulcer healing.

**Correct Answer: C. 6-8 weeks.**