As long as the C certificate is relaxed, you can apply for registration, such as Inner Mongolia, Xinjiang and Tibet. Note that it is registration! When handling cases, the whole country has the right to investigate and collect evidence. It's just that you have to register in the easy zone!
The same is true in Yunnan province, as long as it is relaxed. So it can be done in most places except Kunming!
I am also a C certificate!