What is the most likely complication attributed to this antibiotic?

A 72 year old woman presents to her physician complaining of abdominal pain, frequent and burning micturition. After physical examination and laboratory tests, she is diagnosed with urinary tract infection. She is prescribed gentamicin.
What is the most likely complication attributed to this antibiotic?
A-Hepatic toxicity
B-Hearing loss
C-Thrombocytopenia
D-Agranulocytosis