A-10-year old child has left parasternal heave, apical pan-systolic murmur discovered for the first time. No signs of heart failure, chest-x ray: normal heart size& pulmonary blood flow, echocardiogram reveals mitral valve regurgitation grade 3. The treatment that you will prescribe for him is: a- Digoxin& furosemide. b- Penicillin monthly& before tooth extraction. c- Prednisolone& methotrexate. d- Meloxicam& nifidipine. e- Balloon dilatation of the valve.