The answer to the question will be X i.e the image will be produced at X.
EXPLANATION:
As per the diagram given in the question, the image will be formed due to a plano-concave lens. It is so because the lens is thicker at edge than in the centre and flat on one side.
The source of light is a bulb. The object is present between W and X.
The light rays are appeared to be diverged after being refracted through the lens. So, the lens can not produce any real image.
The rays are appeared to be coming from X when they are produced back, and produces a virtual image at this point. The nature of image will be virtual, erect and diminished.
Hence, the image will be produced at X.
