I was just doing an organic chemistry problem from an online source recently, on the topic of conjugate additions (or 1,4-additions). Below is an image illustrating the problem.

I chose the upper route while the solution manual claims that the answer is the lower route. My rationale for choosing the upper route was that perhaps the alkene is not nucleophilic enough to react feasibly in an electrophilic addition with $\ce {HCl}$. This is due to the presence of the electron-withdrawing carbonyl. Thus, it is important that we first get rid of the carbonyl by using the ethyl Grignard. Then, we can easily add the $\ce {HCl}$ for the electrophilic addition.

Upon reconsidering my reasoning, perhaps I was too narrow-minded in saying that the $\ce {HCl}$ must add in the fashion of electrophilic addition. Perhaps, conjugate addition could also take place. And also, by choosing the upper route, I cannot assure that my chlorine atom would end up in the desired position due considerations of the stability of the carbocation intermediate. Thus, I agree that my choice is incorrect.

The correct choice is the lower route and this does ensure that the $\ce {Cl}$ is in the right place in the final product, as it adds via a conjugate fashion. But how is the writer of the solution so sure that the $\ce {HCl}$ would add in a conjugate fashion, instead of via an electrophilic addition?