The line joining the points $A(2,0)$ and $B(3,1)$ is rotated through an angle of $45^{\circ}$, about A in the anticlockwise direction. The coordinates of B in the new position

Question

\[\begin {array} {1 1} (a)\;(2 ,\sqrt {2}) & \quad (b)\;(\sqrt {2},2) \\ (c)\;(2,2) & \quad (d)\;(\sqrt {2},\sqrt 2) \end {array}\]