One thing the often gets lost in the shuffle is the fact that the ability to take multiple choice tests is a skill. And like any other skill, some individuals are better than others and everyone has the ability to improve with practice. Yes, this test is about orthopaedic physical therapy, but do not neglect this skill set.
Skilled multiple choice test takers like poker players use deductive reasoning and the laws of probability to increase their odds of success. When taking oral or essay exams you have to know the right answer, but multiple choice exams are not the case. You can correctly answer multiple choice questions without knowing the right answer. This bears repeating, you can correctly answer multiple choice questions without knowing the right answer. You might not know the correct response off the top of your head, but you can eliminate choices that you know are wrong. If you can eliminate all but one choice then by default you are left with the correct answer. Even if you cannot eliminate all choices, you still increase your odds of choosing correctly with each one you eliminate.
There are highly skilled test takers out there who can have just modest familiarity with a topic and still score very well on multiple choice exams because of these skills. The OCS exam has 4 and 5 answer choices, so each time you can eliminate a choice you improve your odds of guessing correctly. In some instances, if you can eliminate two choices then there is a 50/50 chance you will choose correctly.
Food for thought, practice, practice, practice, and take all the time you need (there is no bonus for finishing the test early). Make sure you understand what the question is asking, eliminate choices that you know are wrong, and watch your scores improve.