The word is 'converge'

The light rays reflected from Object O will be converged (i.e focused onto a single point) by the lens. The light rays pass through the lens, not reflect back like you see in C.

So only D makes sense.

OMG. Light ray from an object placed a the focal point of the convergent lens will not have a point image. Please do take note. One very common and obvious example/application is spotlight. It can be found in many books.

The answer is D because the question wants a real image. Diagram A, is not giving a shape pointed real image. Theoretically, for A, the image is at infinity.

Diagram A the rays don't even converge. Parallel rays after passing through the lens. Dont even need to consider.

Your first comment mentions focal point. Whether O's position is on the focal point or not is not really relevant to this question, as the main concept tested here is convergence. (i.e where the rays head toward after passing through the lens.)

The spotlight example where object distance (u) = f (focal point to lens centre) should already be internalised by any student taking the O level Physics at this point. If still not clear to them, that would be worrying.

For your reference, Jonathan :

miniphysics.com/ss-ray-diagrams-for-converging-lens.html