"A college senior has already been offered his dream job, conditional upon graduation. However, the student blows off the lower$-$level Gen Ed course you teach for most of the semester, and fails the final exam as well as the course. The student comes to your office, explains his situation, and pleas with you to change his $F$ to a $C$ so that he can graduate and get the job. He knows you are a utilitarian moral theorist and appeals to your utilitarian views as a reason for changing the grade. $\text{'}$If you change the F to a C$,\text{'}$ he says, 'there will be more happiness in the world than if you don't. Plus, so long as neither of us tells anyone, no one will even know that you changed the grade."

According to basic rule$-$utilitarianism, which conclusion is the most correct?

a$.$ It is permissible to change$/$not change the grade.

b$.$ It is an obligation to change the grade.

c$.$ It is impermissible to change the grade.

d$.$ None.