In the Past,ulcers Were Treated by a Bland Diet and Drugs

In the past,ulcers were treated by a bland diet and drugs to reduce the acidity of the stomach.Today,ulcers are often treated with antibiotics.What evidence caused the change in treatment?

A) experiments that showed that antibiotics reduce stomach acidity better than the drugs used prior
B) experiments that showed that Helicobacter pylori infection was the cause of many ulcers
C) experiments that showed that the healing of ulcers required a more acidic, not a less acidic, environment
D) experiments that showed that bland diets actually led to an increase in ulcers
E) experiments that showed that ulcers were most due to stress