Ron and Steven start driving towards each other from two places that are $2000$ metres apart at the same time. When they pass through each other, Ron has driven $500$ metres. What is the ratio of the speeds of Ron to Steven? 
选项为:A:$3:1$  B:$1:3$  C:$2:3$  D:$3:2$  请回答其中一个选项.