The draw was made at Four Continents.
Perhaps not coincidentally, since the Russian Junior National Championships were skated after this draw, the CD the juniors competed at was the Westminster Waltz. I definitely admire the common sense of the Russian Federation for handling it this way.
Now that is smart planning. By holding the Junior championship at the same time as the senior championships (and hence before the 4 Continents draw), both the US and Canadian federations were unable to be sure that the CD they picked for Nationals would be competed at Jr Worlds.
And in the case of the US, it indeed will not. The Argentine Tango was chosen for the Juniors at US Nationals.