As Joinedup has pointed out your “shaky understanding” of focal point or focal length, your problem lies in not understanding the ray drawing.
We can have an image formed not at the focal point as shown below:

If we have a light source that is placed at the focal point, the ray diagram is as shown below. You should notice that the outgoing rays are all parallel to the principal axis.

If the incoming light rays are parallel to the principal axis, the outgoing rays converge at the focal point as shown below again.

With the diagram 2 and 3, the answer to the question should be obvious.