Upgrade subject to access all content

$ { x }^{ 2 }-\left( 2x+1 \right) \left( 2x-1 \right) $ is equivalent to which of the following?

$ { -3x }^{ 2 }+1 $

$ 2{ x }^{ 3 }-5{ x }^{ 2 }+1 $

$ { x }^{ 2 }-4x+1 $

$ -{ x }^{ 2 }+4x+1 $