Task: Question Answering
Input (English): Problem: a clockwise rotation around point z ( that is , a rotation in the direction of the arrow ) transforms the shaded quadrilateral to the unshaded quadrilateral . the angle of rotation is approximately 
Options: a ) 180 o , b ) 270 o , c ) 360 o , d ) 45 o , e ) 135 o
Output (English): b