A Plane Electronmagnetic Wave Is Travelling in the Positive X

Multiple Choice

A plane electronmagnetic wave is travelling in the positive x direction. At the instant shown the electric field at the extremely narrow dashed rectangle is in the negative z direction and its magnitude is decreasing. Which diagram correctly shows the directions and relative magnitudes of the electric field at the edges of the rectangle?

A) A
B) B
C) C
D) D
E) E