If a Rancher prevents a thief from taking his cattle he's enforcing Which principle capitalism?

Freedom of enterprise

Self interest

Private property

Private property, some bandit tries to steal your cattle on your land you cap it buttox. You can still get hanged in Texas for stealing a horse. (Though that never happens.)

Though in seriousness, a Ranch is a business. So if you go into a ranch and steal then he's taking your cattle, keyword your, in this case the Rancher.

If it were you stealing the cattle then I guess you could make a case for self interest.