Hi @grahamandrew,
First things first i would request you to use the correct forum to ask your questions.
As for your question, eGMAT prescribes a negation technique which helps you eliminate the wrong answer options.
1. What is the negation technique?
https://e-gmat.com/blog/gmat-verbal/cri ... -reasoning2. How to negate :
https://gmatclub.com/forum/article-what ... 38510.htmlPlease follow this process once you have eliminated the irrelevant answer options, and are not able to choose
between the last 2 answer choices, you can use the negation technique to find the solution to your question
Hope that helps you!