the answer is the same for questions like this!

A student takes a convex lens and a piece of white card to a window. She moves the lens until an image of a distant building is seen on the card. Another student takes a second piece of card and gradually covers the lens, starting at the bottom.

Consider the following possible consequences:
The top of the image will disappear
The bottom of the image will disappear
The image will become less bright
Nothing will happen until just before the entire lens is covered

what do you think is the most likely answer?