集合 $U=\left\{1,2,3,4,5,6\right\},S=\left\{1,4,5\right\},T=\left\{2,3,4\right\},则S\cap \left(C_{U}T\right)=$（）

A．

$\left\{1,4,5,6\right\}$

B．

$\left\{1,5\right\}$

C．

$\left\{4\right\}$

D．

$\left\{1,2,3,4,5\right\}$