Explanation:

- In 1944, sociologist Ruby Jo Reeves Kennedy introduced the "triple melting pot" theory.

- This theory suggests that true cohesion in the U.S. emerges from religious affiliations.

- Option 1: Religious Groups - According to Kennedy's theory, these groups play a key role in societal cohesion.

- Option 2: Economic Groups - This focuses on financial and wealth-based associations, not directly related to Kennedy's theory.

- Option 3: Ethnic Groups - This refers to cultural or racial identities, which Kennedy didn't emphasize as much in her theory.

- Option 4: Social Groups - This is a broader category encompassing various societal interactions, not specific to Kennedy's focus.