Answer:
1) Japanese buyers of pharmaceuticals.
Instead of focusing on U. S pharmaceuticals, we can look for Japanese buyers of pharmaceuticals. The fact should be acknowledged that if both the policies result in the same quantity which is being imported, then the price paid by the Japanese buyers will be identical as well.
2) Japanese producers of pharmaceuticals.
If both policies are resulting in the same quantity of the import, then the Japanese producers should be indifferent to which trade restriction is selected.