# If $\alpha$ and $\beta$ are the roots of $x^2-2x+4=0,$ then the value of $\alpha ^6+\beta ^6$ is :

$\begin {array} {1 1} (1)\;32 & \quad (2)\;64 \\ (3)\;128 & \quad (4)\;256 \end {array}$

(3) 128