Which one of the following findings is most suggestive of ulcerative colitis?

A 23-year-old man is investigated for chronic diarrhoea associated with raised inflammatory markers. A bowel biopsy is taken. Which one of the following findings is most suggestive of ulcerative colitis?

A. Multiple granulomas
B. Goblet cell depletion
C. Inflammation affecting the serosa
D. Cobblestone appearance