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If $f^{ \prime }\left( x \right) =9{ x }^{ 2 }+8x+6$, which of the following could not be $f(x)$?

$3{ x }^{ 3 }+4{ x }^{ 2 }+6x$

$3{ x }^{ 3 }+4{ x }^{ 2 }+6x-2x$

${ 3x }^{ 3 }+4{ x }^{ 2 }+6x+6$

$3{ x }^{ 3 }+4{ x }^{ 2 }+6x-2$