Empty "grade" field instead of "acceptable" by default

I would love it if there was no grade in the beginning when we start grading. If there are not enough characters in our answer it notifies us but if we forgot to change the grade it does not and I have personally given an A+ work a C. I usually write the answer first and then change the grade but sometimes I submit my grade and get anxious because I don't remember if I changed the grade or not. This could be just a me problem though.

This could be solved by saying "Choose a grade" instead of C and it is unable to be submitted until you choose a grade.