Which of the following statements regarding screw dislocation is correct?

Concept:

• When a dislocation moves under applied shear stress: 
• Individual atoms move in directions parallel to the Burgers vector;
• The dislocation moves in a direction perpendicular to the dislocation line.
• An edge dislocation, therefore, moves in the direction of the Burgers vector and lies perpendicular to the burger vector.
• Whereas a screw dislocation moves in a direction perpendicular to the Burgers vector and lies parallel to burger vector.