It/this/that

[CW Tan]

Q1) Is this number 6?

Q1A) Yes, it is number 6.
Q1B), Yes, this is number 6.

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Q2) Is that number 7?

Q2A) Yes, it is number 7.
Q2B) Yes, that is number 7.

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Dear teachers,

Are Q1A, Q1B, Q2A, Q2B all correct? Or only some of them are correct?

Thank you very much in advance.

[Mister Micawber]

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All four answers are fine.
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