After const copy = Object.assign({}, source), what is guaranteed about a nested object at…

After const copy = Object.assign({}, source), what is guaranteed about a nested object at source.settings?

1. copy.settings and source.settings refer to the same object unless a later source overwrites the property.
2. Object.assign recursively clones settings and preserves no shared identity.
3. Object.assign freezes settings before placing it in copy.
4. The result depends only on whether source was declared with const.