An optician while testing the eyes finds the vision of a patient to be 6/12. By this he means that

• A. the person can read the letters of 6 inches from a distance of 12m
• B. the person can read the letters of 12 inches from 6 m
• C. the person can read the letters of 6 m which the normal eye can read from 12m
• D. the focal length of eye lens had become half that off-he normal eye