This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
All of the following are true about Helicobacter pylori except - 
Select and explain. 
A. About 50% of world population affected, B. 85% of population is affected in some developing contries, C. All childrens in developing countries have immunity by five years of age, D. Infection is common in low socioeconomic status
C: All childrens in developing countries have immunity by five years of age
Answer: C: All childrens in developing countries have immunity by five years of age 
Explanation: None