Would you mind/Do you mind (2)

English as a Second Language English Vocabulary, Grammar and Idioms
1

Which one(s) is/are grammatically correct?

(a) Would you mind if I smoked a cigarette?
(b) Would you mind if I smoke a cigarette?
© Do you mind if I smoked a cigarette?
(d) Do you mind if I smoke a cigarette?

2

All except © which doesn’t make sense as you are asking if they mind now that you already did something.