Mostly pathophysiology - organ systems stuff like you cover in 2nd year. However, there is a good amount of "other" - pharm, micro, biochem, anatomy, etc. Most questions can't really be classified "pathology," "physiology," "pharmacology" -- there are lots of multistep questions that might require you to make the right diagnosis of a disease and then choose the correct drug to treat it, or potential side effects of that drug.