The near point (the smallest distance at which an object can be seen clearly) and the far point (the largest distance at which an object can be seen clearly) are measured for six different people.

near point (cm) far point (cm)
Avishka 40 infinity
berenice 30 300
chadwick 25 500
danya 25 infinity
edouard 80 200
francesca 50 infinity

a. Which, if any of these people are nearsighted (myopic)?
b. Which, if any, of these people require bifocals to correct their vision?
c. Which, if any, of these people's vision can be corrected using only converging lenses?