An 18 year old college student presents to your office for eval of rectal bleeding. You find that blood was seen when she wiped after having a bowel movement; she has been constipated and needed to strain to move her bowels. She denies a family history of color cancer or inflammatory bowel disease. On exam you note a 1cm, round mass at the 10 o'clock position at the rectum externally. What is your most likely diagnosis?
a) external hemorrhoids
b) rectal prolapse
c) uterine prolapse
d) crohn's disease