Typeform API - How to get the key of an answer

Hello ! I am currentlly using the Typeform API, but I need to know the key of an answer.
Here’s an example :

What is your favorite color ?
A: Red
B: Blue
C: Green

In the JSON file, the result is the following for a given answer:
list_XXXXX_choice : Green

I’d like to get the position of green which is “C”. Is there any way to get it ?

PS: I know it is possible to get it by allowing multiple answers, but that’s not what I am looking for.

Thank you :blush: !