Peyer's patches are primarily found here
a. large intestine
b. jejunum
c. duodenum
d. stomach
e. ileum

Ileum.

Explanation:

The small aggregation of lymphatic tissues in the small intestine is known as peyer's patches. They provide an important role in the immune system of the organism.

The peyer patches are present specifically in the ileum region of the small intestine. These patches prevent the individual from the bacterial and pathogen infection.

Thus, the correct answer is option (e).