A research scholar requires $$50\,\mathrm{mL}$$ aqueous $$\mathrm{NaNO_3}$$ solution containing $$70.0\,\mathrm{mg}$$ of $$\mathrm{Na^+}$$ per milliliter. The amount of $$\mathrm{NaNO_3}$$ required for this purpose is

A

$$0.350\,\mathrm{g}$$

B

$$0.161\,\mathrm{g}$$

C

$$29.75\,\mathrm{g}$$

D

$$12.94\,\mathrm{g}$$