mirror image of the point (-1,2) on y-axis is:

a (1,2)

b(1,-2)

c(2,1)

d(2,-1)

Mirror image of point (-1, 2) on y-axis is : (1, 2)

For reference you can check the link below to find the mirror image of a point.

https://www.meritnation.com/ask-answer/question/write-the-mirror-image-of-the-point-3-4-with-respect-to/coordinate-geometry/2842045