How do we use this question tag: "Mustn't you"?

[Sadsnow]

Test No. incompl/elem-35 "Question Tags", question 6

You must go .........

(a) mustn't you?
(b) have you?
(c) had you?
(d) must I?

Test No. incompl/elem-35 "Question Tags", answer 6

You must go mustn't you?

Correct answer: (a) mustn't you?
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You must go .........

(a) mustn't you?
(b) have you?
(c) had you?
(d) must I?
What's the correct answer? Why?

[Torsten]

Hi,

Answer a You must go, mustn't you? is correct.

Mustn't you is a question tag, a phrase that is added to the main part of the sentence, inviting the listener to confirm the opinion of the speaker.

For more information on question tags, please click here:
http://www.english-test.net/forum/ftopic1491.html

TOEIC short conversations: Reordering stationery