A, B, C and D are standing on the four corners of a square field as shown in the figure. From the positions shown in the figure, A walks to North position and B walks to the East position while C decides to walk two sides in anticlockwise direction. B walks to North and then changes his mind to take the previous position. Identify the choice with correct positions.

A

A & B occupy the same position.

B

C & D occupy the same position.

C

D & B are in their original positions.

D

B & C are diagonally opposite positions.