Like you, I didn’t read the supplementary readings attentively! So at the exam, I didn’t have a clue what was being asked. But you may be able to rule out some of the answers that are clearly against the broad principles taught in the core readings, and hopefully narrow it down to a 50-50 choice. The RiskPrep question bank is representative of the exams, and I recall quite a number of questions on the supplementary readings.
Since you haven’t taken the exams yet, don’t neglect the supplementary readings. There are 7 altogether, 3 public domain + 4 under “My Library / PRM Handbook”. I skimmed through all 7 the day before the exam, but they are voluminous & this approach doesn’t work.