The first trick starts: ♦9 - 4 - 5 -?
You are too polite to ask about leads/carding but you are sure LHO has led 4th best from AQJ9(xx).
What's your plan? (In case it matters feel free to assume that the defense will match the standard of the opening lead.)
Arend

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1NT-2♥
2♠-2NT
AP