**Core Concept**
The patient has a non-healing ulcer in the lesser curvature of the stomach, which is a common location for gastric ulcers. The patient's age and the fact that the biopsy is negative for malignancy do not rule out the possibility of malignancy, but rather suggest that the ulcer may be caused by another factor.

**Why the Correct Answer is Right**
The patient has not responded to 6 weeks of H2 blocker therapy, which suggests that the ulcer may be caused by a factor other than acid production. One possible cause is a gastric mucosal blood supply issue, which can lead to mucosal ischemia and ulceration. In this case, the next step would be to assess the gastric mucosal blood supply and consider treatment options such as angiography or surgical intervention.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it suggests that the patient should continue with the current treatment, which has already been shown to be ineffective.
**Option B:** This option is incorrect because it suggests that the patient should undergo another endoscopy, which may not provide any additional information and may not address the underlying cause of the ulcer.
**Option C:** This option is incorrect because it suggests that the patient should undergo a repeat biopsy, which may not be necessary given that the initial biopsy was negative for malignancy.

**Clinical Pearl / High-Yield Fact**
In patients with non-healing ulcers, it is essential to consider other causes beyond acid production, such as mucosal ischemia, and to consider alternative treatment options such as angiography or surgical intervention.

**Correct Answer:** C.