First let us consider the refraction of ray OA by the biconvex lens of focal length 15 cm.

Using the formula

Which gives that the image I' is formed 30 cm from the lens ,i. e. 20 cm from the mirror(to the right of mirror) .

Or we can say that the object for the plane mirror is 20 cm to the right of the plane mirror.

After reflection from mirror a virtual image O' of object I' is formed as shown in the figure above such that O'P = PI',so O' is 10 cm to left of lens (20-10).

Now O' serves as the virtual object for the refraction of ray BC by the lens.

For this refraction u = +10 cm , f =15 cm

i.e image is formed at 6 cm from lens .So the final image I will be formed at 10 cm +6 cm =16 cm from the mirror .

So the image formed is real at a distance of 16 cm from the mirror.

Correct option (B)