The person is able to see clearly and distinctly objects which are placed 25 cm from the eye.
When the plane mirror is placed at 12.5 cm from the eye, the virtual image in the mirror is created at 25 cm from the eye.
So the person is able to see the image clearly.
If the mirror is kept 12.5 cm or more from the eye, then the person can see the image clearly, as the image is created at 25 cm or more from the eye.
If the mirror is kept at distances less than 12.5 cm, then the image cannot be seen clearly.