Cho biết \([3;12)\backslash ( - \infty ;a) = \emptyset \). Giá trị của \(a\) là:

$\left[ {1;2} \right]$

$\left[ {1;2} \right)$

$\left( {1;2} \right]$

$\left( {1;2} \right)$

\(\emptyset \)

\(\left[ {0;5} \right]\)

\(\left[ {3;4} \right]\)

\(\left\{ {3;4} \right\}\)

$R$

\(\emptyset \)

\(\left\{ { - 2} \right\}\)

\(\left( { - \infty ; - 2} \right]\)

\(\left[ {4; + \infty } \right)\)

\(\left( {4; + \infty } \right)\)

\(\emptyset \)

\(\mathbb{R}\)

\(\mathbb{R}\backslash \left[ { - 3; + \infty } \right).\)

\(\mathbb{R}\backslash \left[ { - 3;3} \right).\)

\(\mathbb{R}\backslash \left( { - \infty ;3} \right).\)

\(\mathbb{R}\backslash \left( { - 3;3} \right).\)

$B \cap C = {\rm{[}}2;3)$

$A \cap C = (0;2]$

$A \cup B = R\backslash \left\{ 2 \right\}$

$B \cup C = (0; + \infty )$

\(A \cup B = \left[ { - 2;5} \right]\) .

\(A \cap B = \left[ {0;4} \right]\)

$A\backslash B = \left[ {-2;0} \right]$

$B\backslash A = \left[ {4;5} \right]$