Find the Point on the Curve Given Below at Which $$y = 10 x ^ { 3 } + 31 x ^ { 2 } + 5 x$$

Multiple Choice

Find the point on the curve given below at which the curvature K is zero. $$y = 10 x ^ { 3 } + 31 x ^ { 2 } + 5 x$$

A) $x = \frac { 30 } { 31 }$
B) $x = \frac { 31 } { 30 }$
C) $x = - \frac { 31 } { 30 }$
D) $x = - \frac { 30 } { 31 }$
E) $x = - \frac { 31 } { 10 }$