The ancient Romans used Roman numerals. We still use them today. Here are some examples: $$\rm I=1$$, $$\rm II=2$$, $$\rm V=5$$, $$\rm IX=9$$, $$\rm X=10$$, $$\rm XI=11$$, $$\rm XX=20$$. This year($2022$) we celebrate Math Kangaroo number $$\rm XX$$. What year was Math Kangaroo number $$\rm XV$$? 
选项为:A:$$2015$$  B:$$2016$$  C:$$2017$$  D:$$2018$$  E:$$2019$$  请回答其中一个选项.