I passed all of my final exams now i can prepare for graduation.
which is not a run on sentence
a.I passed all of my final exams now, i can prepare for graduation.
b. I passed all of my final exams, now i can prepare for graduation.
c. I passed all of my final exams; now i can prepare for graduation.
d. I passed all of my final exams, now, i can prepare for graduation.