Which amendment has been interpreted as the foundation of implied rights?

second amendment
fourth amendment
eighth amendment
ninth amendment

The amendment that has been interpreted as the foundation of implied rights is the Ninth Amendment.

Explanation:

The Ninth Amendment to the United States Constitution is part of the United States Bill of Rights, and protects rights that are not expressly enumerated in the Constitution, as it states that "The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people".