Correct option is (b) A \(\cap \) B = {4, 6, 8, 10}
A = {x \(\in N \) : 3 < x < 12}
∴ A = {4, 5, 6, 7, 8, 9, 10, 11}
and B = {x \(\in N \) : x is even & x < 15}
∴ B = {2, 4, 6, 8, 10, 12, 14}
Then A \(\cup\) B = {2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14}
A \(\cap \) B = {4, 6, 8, 10}
A/B = A - B = \(\phi\)
B/A = B - A = {2, 12, 14}