Miley had some keychains at first. She gave $$\frac{6}{7}$$ of them to her friends. Her mother then gave her another $$8$$ keychains. She had $$15$$ keychains in the end. How many keychains did Miley give to her friends in total? 
选项为:A:$$42$$  B:$$48$$  C:$$49$$  D:$$90$$  请回答其中一个选项.