Which citator is commonly found on nonfee-based websites?

The correct choice is Authority Check, which is commonly found on non-fee-based websites. Authority Check is a free legal research tool that provides information about the citation status of legal documents and helps users verify whether a case or statute is still good law. It typically aggregates resources from publicly accessible legal databases, making it valuable for researchers and practitioners who do not have access to subscription-based legal research platforms.

Other options, such as MainCheck, Sherpa Guide, and LawTrack, are either specific to certain subscription services or less widely recognized as free resources in the realm of legal citation checking. They may provide helpful functions within their respective systems, but do not offer the same level of accessibility on non-fee-based websites as Authority Check does.