We know that "a good manager must understand people and be able to defuse tense situations."
GM --> UP and DTS Not UP or Not DTS --> Not GM
The passage also tells us that, if you are able to defuse tense situations, you must understand people.
DTS --> UP Not UP --> Not DTS
The passage concludes that since Ishiko is able to defuse tense situations, she must be a good manager.
The flaw here is that the passage draws a conclusion about the sufficient condition based on the existence of the necessary condition (i.e. improperly reversing our first conditional diagram above).
In this way, the passage mistakenly concludes that qualities that are necessary for being a good manager are also qualities that guarantee being a good manager (i.e. are sufficient).
The conclusion drawn is about being a good manager, not being able to understand people. This is why answer choice (C) is correct over answer choice (A).
Hope this helps! Please let us know if you have any further questions.
