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Evaluate the following:

$$\int { \cfrac { 1 }{ \sqrt { -{ x }^{ 2 }+6x } } } dx$$

$\ln { \sqrt{ ( { -x }^{ 2 }+6x )}} +C$

$2 \sqrt {( 9-( x-3 ) ^{ 2 } )} +C$

$-2 \sqrt {( 9-( x-3 ) ^{ 2 } )} +C$

$\arcsin {\dfrac{ x-3}{3}} +C$