I am so confused by the wording of AC B. "Obtain" is a transitive verb, which means it needs an object. I really think it needs to be "state of affairs does not obtain [a result]" or "a state of affairs does not obtain that with which..." or something; as written, it reads as gibberish... If this is truly as it was written in the LSAT, I'll have to reach out to LSAC - this is driving me up a wall!!!

I vote test center 100 percent! Either way the exam is administered on a computer. August and September administrations have had issues online, so I would play it safe at go to a Prometric center. I have taken many other exams at a test center and have never had an issue with them