An 8 yrs old boy had abdominal pain,fever with bloody diarrhea for 18 months.His height 100 cms and weight is 14.5 kg.Stool culture was negative for known enteropathogens.The sigmoidoscopy was normal.During the same period,child has an episode of renal colic and passed urinary gravel.The mantoux test was 5x5 mm.The most probable diagnosis is:

• A. Crohn's disease
• B. Ulcerative colitis
• C. Strongyloidosis
• D. Interstinal tuberculosis