The key to this question's answer is to avoid the Shell answers like option D. In most of strengthening CR, one of the option choices will be therewhich compares the current argument's conclusion with other scenario's conclusion . We need to straight away eliminate it to get the right answer. Thus avoiding one of the GMAT CR traps.
Another Example for practice :
https://gmatclub.com/forum/cr-revision-
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Another Example for practice :
https://gmatclub.com/forum/cr-revision-
...






