Extracting recode values for dropdown mcq using jQuery

I have a simple dropdown for participants to select their year of birth. I want to create a variable under addOnPageSubmit that will give me the recoded value for this question. I can’t use 

var age = this.getChoiceRecodeValue(this.getSelectedChoices()); 

since the js has to be in a different question on the same page. Ideally, I would want something like the below

var age= jQuery("#QID209 option:selected"); 

However, I can’t figure out how to get the recode values using this :( 

Any help is appreciated!