Looks like a 90 degree rotation right to me, so answer is #4 but I'm no Wiz, I'm just an Authority figurehead on here :-)

1) "In trigonometry, and mathematics in general, plane angles are conventionally measured anticlockwise." Source and further information: http://en.wikipedia.org/wiki/Clockwise_and_counterclockwise 2) "In geometry and linear algebra, a rotation is a transformation in a plane or in space that describes the motion of a rigid body around a fixed point. A rotation is different from a translation, which has no fixed points, and from a reflection, which "flips" the bodies it is transforming. A rotation and the above-mentioned transformations are isometries; they leave the distance between any two points unchanged after the transformation." Source and further information: http://en.wikipedia.org/wiki/Rotation_(mathematics%29 3) transformation: r[y=x] o R[90°] I understand the transformation as doing first a rotation of 90° in the anticlockwise direction, and after this a reflection between the x and the y axe. With the rotation, you would get answer number 1. (you segment comes from the 1st to the 2nd quadrant) When you take answer 1 and make then the reflection, you get answer 3. (you segment comes from the 2nd to the 4th quadrant)