Luna, Lily, and Lucy are talking about their ages. $6$ years ago, Luna was born, and Lily was $5$ years old. This year, the sum of ages of these $3$ people is $33$. When Luna was born, how old was Lucy? 
选项为:A:$$7$$  B:$$8$$  C:$$9$$  D:$$10$$  E:$$11$$  请回答其中一个选项.