12.设全集U={−1U=\{-1U={−1,1,2,3}3\}3},集合A={−1A=\{-1A={−1,2}2\}2},B={x∣x2−2x−3=0}B=\{x\vert x^{2}-2x-3=0\}B={x∣x2−2x−3=0},则∁U(A⋂B)=(\complement _{U}(A\bigcap B)=(∁U(A⋂B)=( )))