The tone in the following sentence is . Please allow me the opportunity to argue for a better grade.

Reasonable

Explanation:

A reasonable tone is most times applied in arguments when a person wants another person to view things from his own standpoint. Instead of shouting or being rude, you argue persuasively to make your points and convince the other person to accept your viewpoint. In the sentence above, the student likely was given a grade which he believes was not right. Instead of making a fuss about it, he pleads that he should be allowed to argue for a better grade.

This tone is reasonable because it appeals to logic and if a proper argument is eventually presented, he can convince the other about why he should have a better grade.

you need to include the text. we have no idea what you are referring to