Correct answer: B. Selenium exposure.
Helicobacter pylori infection is by far the most important risk factor for gastric cancer worldwide. Less common risk factors for gastric cancer include Lynch syndrome, Peutz-Jeghers syndrome, Menetrier's disease, and germline mutations in the CDH gene (encoding E-cadherin). However, there is some evidence that selenium, as well as high consumption of fruits and vegetables, may have protective effects against gastric cancer.
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