5 A Hi. Can you talk or are you driving / do you drive? B I don't drive / I'm not driving, but I can't talk now. I have / I'm having lunch with my boss.

5 A Hi. Can you talk or are you driving? B I'm not driving, but I can't talk now. I'm having lunch with my boss.

Объяснение: В вопросе интересуются, не занят ли человек в данный момент вождением, поэтому используем Present Continuous (are you driving). Ответ также относится к текущему моменту, поэтому используем Present Continuous (I'm not driving, I'm having).