swutc2019

I am trying to submit English Language, Spoken English grades (8700/C) in Progresso. Progresso is asking me for either a D, M, P, or NC grade, which I have. But I cannot submit these grades without selecting either A, E, F, G, M, N, V, or Z as well for each student. I have no idea what these letters relate to and would really appreciate any help please.