The main health complaint of a 52 year-old male patient was constipation for the past six weeks. During the past two months he has lost five pounds without dieting or exercising. The pulse was regular at 70 bpm. The abdominal exam was normal. Your recommendation is to increase dietary fiber, treat with acupuncture + herbs, and
选项：

A:have patient purchase a blood stool test kit at pharmacy
B:refer patient to primary care physician for endoscopy
C:refer patient to primary care physician for colonoscopy
D:refer patient to primary care physician for barium enema