A 35 years old hispanic male comes to the office because of excruciating pain during defecation for the past week. the pain is so severe that he avoids use toilet. He also adds he has noticed bright red blood in stool. The caliber of his stool hasn't changed. His past medical history is significant for chronic constipation. Rectal examination shows a posterior mucosal tear of the anus. Which of the following most appropriate next step in management?
a) Colonoscopy.
b) Local anesthetic and stool softeners.
c) Lateral sphincterotomy.
d) Antibiotics.
