What Compromise Did the Delegates at the Philadelphia Convention Reach

What compromise did the delegates at the Philadelphia Convention reach on the question of the importation of slaves from foreign lands?

A) The trade could not be abolished without the unanimous consent of all of the states.
B) The trade would be ended immediately,though it could be reopened after twenty years should Congress vote in favor of it.
C) Congress would have the power to decide whether or not to end the trade,but would not be able to exercise that power for twenty years after the new government came into being.
D) Twenty years after the new government came into being,the slave trade would automatically come to an end,with or without action from Congress.