Non valvar vs rheumatic valvar AF – Cardiology MCQ

True statement/s regarding risk of stroke in non valvar vs rheumatic valvar atrial fibrillation (AF):
a) Risk of stroke in rheumatic valvar AF is 17 times higher than age matched controls
b) Five fold increase in risk of stroke with valvar AF
c) Risk of stroke is higher with rheumatic valvar AF
d) All of the above