An ulcer can occur when a small hole or tear forms in the lining of the stomach. Ulcers can be caused by high levels of certain bacteria in the stomach and by lifestyle choices, such as heavy smoking, heavy drinking, and overuse of pain relievers. An estimated one in ten Americans will suffer from ulcers during their lifetime. However, most ulcers are relatively easy to treat with antibiotics and medications that help lower the production of acids by the stomach. Which tissue is most directly affected by the formation of an ulcer in the stomach?

a epithelial
b connective
c nervous
d muscle