Given that:
[tex]U=\lbrace1,2,3,4,5,6,7\rbrace[/tex][tex]\begin{gathered} A=\lbrace2,4,6\rbrace \\ B=\lbrace1,2,3,5,7\rbrace \\ C=\lbrace1,3,6,7\rbrace \end{gathered}[/tex]1, You need to find:
[tex]B\cap C[/tex]In order to find the intersection of sets B and C, you need to identify the numbers both sets have in common. Then, you get:
[tex]B\cap C=\lbrace1,3,7\rbrace[/tex]2. Find:
[tex]A\cap(B\cap C)[/tex]You need to identify the numbers that these sets have in common:
[tex]A\text{ }and\text{ }B\cap C[/tex]Therefore, you get:
[tex]A\cap(B\cap C)=\lbrace\rbrace[/tex]Hence, the answer is: Option a.