GMAT Sentence Correction (SC) | Re: Whether they will scale back their orders to pre-2003 levels or stop

The issue here is whether they will do this or that. Therefore, a dilemma is involved and an answer to the dilemma is required. The correct diction for this expression is indeed whether or as Warriorguy correctly pointed out. If is used when you want to say, if this happens the other thing will happen. This means that if A happens then B will certainly happen. However, in the given context, it is not clear as to what will happen, if the proposed changes are fully implemented. Whether they will