Final answer:
A virtual image has a positive image distance (q) and is located in the back of the lens. So the correct answer is Option C.
Step-by-step explanation:
The correct answer is C. A virtual image has a positive image distance (q) and is located in the back of the lens.
When dealing with lenses, a positive image distance indicates a real image that is formed on the opposite side of the lens from where the object is placed. On the other hand, a negative image distance indicates a virtual image that is formed on the same side of the lens as the object.
In this case, a virtual image is formed, which means it is located in the same side of the lens as the object. Therefore, the correct answer is C.