A nearsighted person cannot see objects clearly beyond $70cm($the far point$).$ If contact lenses are prescribed, what is the power of the lens required to correct the patient's vision?

$7\mathrm{.}0$ diopters

$0\mathrm{.}7$ diopters

$1\mathrm{.}4$ diopters

$2\mathrm{.}9$ diopters