A mass $$0.75\,g$$ of the mixture of $$Na_{2}CO_{3}$$ and $$K_{2}CO_{3}$$ is completely neutralized by $$50\,mL$$ $$0.25\,N$$ $$HCl$$. The percentage of $$Na_{2}CO_{3}$$ in the mixture is

A

50.6

B

49.4

C

50

D

data insufficient