Renal function was similar to 3 months ago. What is the most appropriate action?

A 62-year-old man with a diabetic nephropathy and hypertension is reviewed. His current medication is insulin, bendroflumethiazide, ramipril and amlodipine. On examination blood pressure is 144/78 mmHg. Blood tests reveal the following:

Na+ 139 mmol/l
K+ 4.9 mmol/l
Urea 12.8 mmol/l
Creatinine 215 µmol/l
eGFR 29 ml/min

Renal function was similar to 3 months ago. What is the most appropriate action?

A. No change to his medication
B. Switch bendroflumethiazide to furosemide
C. Add a beta-blocker
D. Add spironolactone
E. Stop ramipril