**Core Concept**
The question is testing the understanding of the complications that can arise in patients with chronic peptic ulcer disease, specifically the development of a complication that leads to worsening of symptoms. The correct answer involves the pathophysiological changes that occur in the stomach and duodenum.

**Why the Correct Answer is Right**
The patient's symptoms of worsening of symptoms, loss of periodicity of symptoms, pain on rising in the morning, sense of epigastric bloating, and post-prandial vomiting suggest the development of gastric outlet obstruction. This is likely due to the formation of a gastric or duodenal ulcer that has perforated and led to the development of a fibrotic scar, causing the gastric outlet to become narrowed and obstructed. The narrowing of the gastric outlet leads to a mechanical obstruction, preventing the normal passage of food from the stomach into the small intestine. This is a well-known complication of chronic peptic ulcer disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not directly relate to the complications of chronic peptic ulcer disease. While gastritis can be a complication of peptic ulcer disease, it is not the most likely cause of the patient's worsening symptoms.
**Option B:** This option is incorrect because it is a treatment for peptic ulcer disease, not a complication. Proton pump inhibitors (PPIs) are used to reduce stomach acid production and promote healing of ulcers.
**Option C:** This option is incorrect because it is a sign of gastric outlet obstruction, but it is not the underlying cause. The patient's symptoms of post-prandial vomiting and epigastric bloating suggest a mechanical obstruction, but this is a result of the underlying complication, not the complication itself.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that patients with chronic peptic ulcer disease are at risk of developing gastric outlet obstruction due to the formation of fibrotic scars. This can lead to a mechanical obstruction, which is a medical emergency that requires prompt treatment.

**Correct Answer:** C. Gastric outlet obstruction