SOLUTION
From the question, we have
A = {3, 4, 7, 9}
B = {8, 9, 10, 11}
C = {4, 9, 11, 13, 15}
To get this lets first find B union C. This is all the items found in B or C or both, but not repeated. So B union C is
[tex]B\cup C=\lbrace4,8,9,10,11,13,15\rbrace[/tex]
Now A intersection B union C are the elements common to set A and set B union C. We have
[tex]A\cap(B\cup C)=\lbrace4,9\rbrace[/tex]
Hence the first option is the answer
