Question

You must/should/ought to be punctual.
Plz give reasonable and justified answer

Answer 1

Must..

You must be punctual...

Hope this helps you

Answer 2

Ello user !!!!!!

Here is your answer,

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You ought to be punctual.

Reason - must to be and should to be doesn't follow english grammar rules.

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HOPE THIS HELPS YOUU :)

AND STAY BLESSED.