A 60 year old man presented with fatigue, weight loss and heaviness in left hypochondrium for 6 months. The hemogram showed Hb. 10gm/dL,TLC 5 lakhs/mm3, platelet count 4 lakhs/mm3, DLC: neutrophil 55%, lymphocytes 4%, monocytes 2%, basophils 6%, metamyelocytes 10%, myelocytes 18%, promyelocytes 2% and blasts 3%. The most likely cytogenetic abnormality in this case is -
t (1 : 21) t (9:22) t (15:17) Trisomy 21