Which answer shows a reflection across the y-axis?

A
B
C
D

D

Step-by-step explanation:

The y axis is the vertical axis; the one going up and down.

A reflection means that a point is an equal distance away from its reflector as the basis was.

A was a reflection across the line y=x.

B was a reflection across the x axis with a 90 degree rotation.

C was a reflection across the x axis.

That leaves D.