GMAT Critical Reasoning (CR) | Re: Meat from chickens contaminated with salmonella bacteria can cause ser

Its always easier to solve CR questions when you figure out what exactly is the argument saying.

Look at the question stem -"In deciding whether the feed would be useful in raising salmonella-free chicken for retail sale"
The argument's conclusion then would be - useful in raising salmonella-free chicken for retail sale.

Then I can write the argument as-
chicken feed laced with capsaicin --> useful in raising salmonella free chicken for retail sale.