Surgery started at 0810.
The surgery lasted 3 and 1/2 hours, so it finished at 0810 + 3:30 = 1130.
After surgery, the patient spent another 1 and 1/2 hours in recovery, so the total time elapsed is 1130 + 1:30 = 1300.
Therefore, the patient was discharged at 1300, so the correct answer is:
c. 1300