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