white cell count3.6 ?

A 58-year-old man presented with tiredness and breathlessness. He had been treated for type 2 diabetes mellitus and hypertension for the past 10 years. He was free of complications. His current medication included ramipril 10 mg daily, rosuvastatin 10 mg daily, metformin 500 mg three times daily, dapagliflozin 10 mg once daily and exenatide 10 micrograms twice daily.

On examination, his body mass index was 36 kg/m2 (18C25).

Investigations:

haemoglobin93 g/L (130C180)

MCV110 fL (80C96)

white cell count3.6 ? 109/L (4.0C11.0)

platelet count140 ? 109/L (150C400)

reticulocyte count0.5% (0.5C2.4)

serum ferritin250 µg/L (15C300)

serum vitamin B1240 ng/L (160C760)

serum folate3.0 µg/L (2.0C11.0)

Which medication is most likely to be contributing to his anaemia?
A . dapagliflozin
B . exenatide
C . metformin
D . ramipril
E . rosuvastatin