Yes. Treat the client's preferred answer as a hypothesis, not as the conclusion you are supposed to prove.

Your job in the case is to test whether that option actually solves the client's objective. If you structure only around confirming it, you can miss a better alternative or an important reason the preferred path will not work.

If the client wants to enter a market through an acquisition, you can test the acquisition economics while still comparing them with organic entry, partnerships, or not entering at all. The alternatives do not need equal depth, but they should remain logically possible.

State the client's preference, explain the criteria you would use to test it, and keep at least one credible alternative in the structure until the evidence rules it out. If useful, this guide on case structure vs. case framework gives more detail.

I think this is basically hypothesis testing. client preference shouldn't become your answer automatically.

Had a case like this and my interviewer liked that I still kept a real alternative alive.