Simple present tense is used to ask general questions/ make generalized statements. Here, we are referring to what the person does, which is a fact or general truth about that person. Hence, we use the simple present tense. The syntax for simple present tense (in interrogation) is: Do (es) + subject + Verb in its first form ( wIth singular subject) / Do + subject + verb in its first form (with plural subject). 'I' & 'You' are exceptional cases which, in spite of being singular subjects, take the verbs of plural subjects. Therefore, the correct option is: do you do.