Jack mixed $20$ grams of sugar with $30$ grams of water. What is the percent concentration of the sugar solution? Then Jack added $50$ grams of water. What is the percent concentration the sugar solution? 
选项为:A:$$40 \textbackslash\% $$; $$20\textbackslash\% $$.  B:$$40 \textbackslash\% $$; $$25 \textbackslash\% $$.  C:$$50 \textbackslash\% $$; $$20 \textbackslash\% $$.  D:$$50 \textbackslash\% $$;~$$25 \textbackslash\% $$.  请回答其中一个选项.