With critical reasoning, the most important thing is to read the question, and understand what your job is. Some questions are simple, “what is the assumption,” whereas others are extremely convoluted. They say something like, “which of the following does not support the finding that the conclusion is wrong.” All the double negatives can make it very tough to figure out what’s what.
Strip it down to, “why is X a bad idea.” And then pose this question to each answer choice. You need to set up specific criteria for the answer choice. If it doesn’t say why X is a bad idea, cross it off and move on. If you don’t specify what you want out of the answer choice, it’s like walking into the grocery store without a shopping list. You will be lured to pick things that you don’t need and forget about why you went there in the first place.