My aunt can fold $$16$$ paper cranes in $$4$$ minutes. My uncle can fold $$15$$ paper cranes in $$5$$ minutes. How long would it take them to fold $$42$$ cranes if they work together at those rates?　 
选项为:A:$$6$$ minutes  B:$$9$$ minutes  C:$$12$$ minutes  D:$$13$$ minutes  请回答其中一个选项.