Final answer:
The image formed by a convex mirror when an object is placed at a distance of 2/3f from the mirror will be upright and reduced in size, known as a case 3 image.
Step-by-step explanation:
When an object is placed in front of a convex mirror, the type of image formed can be predicted based on the properties of the mirror. A convex mirror has a diverging effect, which is indicated by its negative focal length (f is negative). Since the object is placed at a distance of 2/3f from the mirror, which is less than the focal length, we use the properties of convex mirrors to determine the characteristics of the image formed.
According to the properties of convex mirrors, it always forms an image that is virtual, meaning that it cannot be projected on a screen and appears to be behind the mirror. The image is also upright (maintains the same orientation as the object) and reduced (smaller in size compared to the object). This is known as a case 3 image for a convex mirror. Therefore, the correct answer to the student's question would be that the image will appear A. upright and reduced.