All the following polyps are premalignant except:

Juvenile polyps which occur as solitary juvenile polyp or multiple juvenile polyps (2-4 polyps) have negligible malignancy risk. But Juvenile polyposis syndrome (greater than 5 polyps) has a definite malignancy risk of 30-60%. Familial adenomatous polyposis, if left untreated has a 100% relative risk of turning into malignancy. The relative risk of developing small bowel carcinoma in Peutz Jeghers syndrome is 18 fold greater than general population. So, the single best answer for the above question is juvenile polyp considering it as a solitary juvenile polyp. Ref: Current Surgical Diagnosis & Treatment, 12th Edition, Page709, 710,682; Bailey and Love's sho practice of surgery 24th edition page 1175-6; Harrison's Principles of Internal Medicine 18th edition, page 769- 770.