13 . please i need the answer

Mazaya Company wrote checks totaling R O.8,540 during May and R.O.9,325 during June. R.O.8,120 of these checks cleared the bank in May, and R.O.9,101 cleared the bank in June. What was the amount of outstanding checks on June 30? Select one: O a. R.O.690 O b. R.O.644 O C. R.O.615 O d. R.O.635