How does VueJS select an option in a select?

Question

Vue.js

How does vue select an option in a select?
The page is generated by django, then when choosing in one select, the second select changes.
For example:
First select:
1. Minutes from 01/01/2018.
2. Minutes dated 02.02.2018
2. Minutes dated 03.03.2018
Second:
1. CHI
2. VMP
When choosing from the first 1, 2 is set.
When choosing from the first 2, 2 is set.
When choosing from the first 3, 1 is set.
As I did before. I made a request through axios, which returned VMP or OMS (VMP) and automatically changed the second select.
Now it looks like VMP, what do I need to return in the query in order to select this option, VMP or 1?