There are four textbook answers on the "properties" of image of an object placed at the focal point in front of a converging lens.
1. No image is formed.
2. 2 images are formed, one real and one virtual located at infinity.
3. A virtual image located at infinity, upright and magnified.
4. A real image located at infinity, inverted and magnified.
Should there be only one correct answer? Or is there a better answer?