Which mirror shows lateral inversion of light?

The correct answer is plane mirror.
Plane mirror shows lateral inversion of light. Lateral inversion refers to the image seen which is inverted in terms of left and right. The left part of an object is seen on the right side virtual image in the mirror and vice versa.

Convex mirror forms diminished image. The centre of the curvature lies behind the mirror
Concave mirror either forms an enlarged image or a diminished one, depending upon the position of the object. The centre of the curvature lies in front of the mirror.