Okay. I think this makes sense.
I would ask what happens when you change answer choice B to say "which are due to an oversupply", but two more things come to mind:
1. The meaning starts to shift -- that is, the "which are due to an oversupply" would be an nonessential modifier, but the author of the sentence probably doesn't consider this a nonessential statement. After all, the oversupply was the first domino to fall and led to the cut in production.
2. I suppose it's not
...
I would ask what happens when you change answer choice B to say "which are due to an oversupply", but two more things come to mind:
1. The meaning starts to shift -- that is, the "which are due to an oversupply" would be an nonessential modifier, but the author of the sentence probably doesn't consider this a nonessential statement. After all, the oversupply was the first domino to fall and led to the cut in production.
2. I suppose it's not
...
