Basically, no one will get a B on purpose, unless they are announcers or actors, and it is expressly stipulated that they need to get a B.
One or two will take the exam in Guiyang, and generally one or two will save the exam! Moreover, the requirements will be stricter than dimethyl, and there will be three minutes of free speech, which must be finished in three minutes and cannot be intermittent. You can consult your school teacher or Putonghua tester for specific requirements.
Southerners generally have some areas influenced by dialects or with imperfect pronunciation, such as nasal sounds and flat tongue sounds.
Not everyone can speak Mandarin well at birth. As long as you have determination and perseverance, practice and change frequently, there will be no problem. Good luck.