How do you convience my professor to change your grade?

You see I got a C in biology but i was expecting a B, I did all work assignments, and extra credit to bring my grade up and I thought i did...How do you convience my professor to change your grade?
first ask him if he likes chocolate.....How do you convience my professor to change your grade?
You could respectfully ask your professor if he would review your grade with you, and explain to you how it was calculated. It is possible, however, that the extra credit was insufficient to bolster your grade.
Meet with the professor and discuss your options to raise the grade. In the future, meet regularly with your professors to discuss your progress and measures to meet the course criteria.
ask him what grades you got and calculate your grade yourself. if there is a difference say to him ';i found my grade average and it is different from what you gave me, how did you do the grading'; it is possible that they made a mistake. If you want to get higher on a paper, present and good argument about why your point is correct