Acute chronic gastritis peptic ulcer disease

Which of the following is a differentiating factor between gastric ulcers and duodenal ulcers?

1: Duodenal ulcers cause melena.
2: Gastric ulcers are associated with H. pylori infection.
3: The most common location of a perforation is in the stomach.
4: The pain of duodenal ulcers tends to improve with a food bolus.