I'm not sure what this program is doing.
Let me write some pseudo code of what it does:
grades = readGrades();
if (grades.Any(grade < 4)) consultationIsMandatory = true;
if (grades.Any(0 <= grade && grade < 7)) consultationIsAdvised = true;
if (grades.All(7 <= grade)) consultationIsOptional = true;
So to me it means that if all the grades are at least 7, then all is good.
However, it's strange that for grades less than 4 consultations are mandatory and advised at the same time. Did you want to make advised for range [4, 7[ perhaps?
Also, without having the test cases, it's hard to tell why exactly they fail. At least the requirements would be nice to have so we know what the program is supposed to do.
I haven't noticed xDELLx's post when I posted mine. It seems like we had the same idea. :)