Under §61.215 Ground instructor privileges, it says
(a) A person who holds a basic ground instructor rating is authorized to provide—
(1) Ground training in the aeronautical knowledge areas required for the issuance of a sport pilot certificate, recreational pilot certificate, private pilot certificate, or associated ratings under this part;
(2) Ground training required for a sport pilot, recreational pilot, and private pilot flight review; and
(3) A recommendation for a knowledge test required for the issuance of a sport pilot certificate, recreational pilot certificate, or private pilot certificate under this part.
But it doesn't say anything about what kind of category and class the ground instructor may instruct on. Is a separate GI rating required for each category and class? or is there one GI rating that covers all categories and classes?