$16.$ Without corrective lenses, the closest object a patient can clearly see without straining is $50$ cm away. Which of the following corrective lenses should this person chose to clearly see $($without straining$)$ objects held $25$ cm away? Ignore the distance between the eye and the corrective lens.

A$.+2\mathrm{.}0$ diopters.

B$.-1\mathrm{.}0$ diopters.

C$.-2\mathrm{.}0$ diopters.

D$.+1\mathrm{.}0$ diopters.

E$.+2\mathrm{.}5$ diopters.