It depends on which subject it is. It’s mentioned in the High School Entrance Examination Manual!
If it is a mathematics subject, there is a clear requirement to use 2B pencils for drawings.
If it is a physics subject, it is OK to use a 2B pencil, a black marker pen, or a black pen.
However, our teacher told us that it is best to use 2B pencils for drawing, because machine scanning is more sensitive to 2B.
But if you use 2B to draw, it will be darker than the standard line.
Actually, you don’t have to worry, usually drawing is no problem.
I am also a fresh graduate this year~