Final answer:
A pencil viewed through a concave lens forms an image that is virtual, upright, and smaller than the actual object, characteristics typical of a case 3 image formed by a diverging lens.
Step-by-step explanation:
When a pencil is viewed through a concave lens, the image that is formed is characteristic of what is known as a case 3 image. A concave lens, which is a diverging lens, can only form virtual images. These images are always upright, and for a concave lens, they are always smaller than the object. This characteristic is due to the diverging nature of the lens, which spreads out the light rays coming from the object so that they appear to be coming from a point closer to the lens on the same side as the object. Therefore, when viewing a pencil through a concave lens, the correct description of the image would be upright, smaller than the actual object, and virtual, as the image cannot be projected on a screen.