No national productivity measures are available for underground industries that may exist but remain unreported. On the other hand, at least some industries that are run entirely by self - employed industrialists are included in national productivity measures. From the information given above, it can be validly concluded that

there are at least some industries run entirely by self - employed industrialists that are underground industries

no industries that are run entirely by self - employed industrialists operate underground.

there are at least some industries other than those run entirely by self - employed industrialists that are underground industries.

there are at least some industries run entirely by self - employed industrialists that are not underground industries