If Sites Are Located During a Survey and Are Determined

If sites are located during a survey and are determined eligible for the National Register they might be slated for "data recovery", which means

A) excavations and associated analyses of the artifacts, ecofacts, and sediments.
B) excavations sufficient to ensure that information is not lost.
C) securing the site and making it off limits to the general public.
D) proposing a well-reasoned research question to combat threat to the site from looting or construction activities.