The evidence that best supports the conclusion that Katherine broke social norms and barriers for women, specifically Black women, is found in option B:
“She played cards and talked about aviation magazines with her white male colleagues during breaks. She even successfully demanded that she be allowed to attend high-level briefings.”
This statement highlights Katherine's ability to engage with her white male colleagues in a domain where racial and gender barriers were prevalent, illustrating her defiance of societal norms of the time regarding race and gender roles in the workplace. Additionally, her successful demand to attend high-level briefings indicates her determination and capability to assert her professional worth in a male-dominated and racially biased environment.