Answer:
A) Please allow me the opportunity to argue for a better grade
Step-by-step explanation:
Problematic means being doubtful, full of problems, uncertain and being questionable while tone means a vocal sound that expresses or shows one feelings or thoughts.
From the above definitions, we can now say that a problematic tone entails when a speaker expresses his feelings in a doubtful or questionable manner.
So, from the question, the statement where the speaker expresses his feelings in a doubtful manner is the statement
"Please allow me the opportunity to argue for a better grade".
In the statement the speaker is doubtful of the grade he/she was given, and it seems the speaker is contesting the decision. The speaker feels he deserves a better grade.