Seeing a breakdown means seeing a cookie-cutter or generic question/stimulus model, right? So what you’re saying is improvement in speed is largely dependent on drilling certain question types in order to recognize latent patterns.
You can use older PTs for drills. And do some 60s,70s,80s. When you don't feel confident with your fundamentals, use older PTs to practice. They're more cookiecutter and they can help you see the pattern more easily.
A--->B ... us a with a valid argumentform. JY talks about it in ... us with the same valid argumentform and therefore, it cannot be ... does clearly reflect the logical form provided in the stimulus.
I don't think they favour valid or invalid arguments in this question type. They just want you to parallel the reasoning structure. You're correct to suggest thats an invalid argumentform. So the answer choice has to make that same error.