In the question 6, the correct answer includes all the options excluding third option but I also selected third answer. I want to give an explanation as to why I chose this and want to understand why am I wrong-
Since repeated elements are only counted once so {x,x} can be written as just {x} so by that logic since x is present in both the sets it would also be present in the AUB. So, why is third option not selected in the answer key.
