Given func (job *Job) Cancel(), which compile-time assertion can succeed for interface{ C…

Given func (job *Job) Cancel(), which compile-time assertion can succeed for interface{ Cancel() }?

1. var _ interface{ Cancel() } = (*Job)(nil)
2. var _ interface{ Cancel() } = Job{}
3. var _ *Job = interface{ Cancel() }(nil)
4. Both Job{} and (*Job)(nil)