Good opponents bid undisturbed
1♥-1♠
2♦-3♣*
3♥-...4♥
1♥ was limited to 15 hcp.
Opps are good, but they are not very sure this is the best contract - a certain nervousness can be felt, screens notwithstanding. When I ask RHO "did you promise 6-4 here?", he answers something along the lines of "well dude if you don't understand a natural sequence, then I can't do anything for you".
What do you lead?

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