<div id="app">
  <select v-model="selectedCity">
    <option
      v-for="city in cities"
      :key="city.value"
      :value="city.value"
    >
      {{ city.label }}
    </option>
  </select>
  {{ selectedCity }}
</div>

const app = new Vue({
  el: '#app',
  data() {
    return {
      selectedCity: 'nsk',
      cities: [
        { value: 'msk', label: 'Москва'},
        { value: 'spb', label: 'Санкт-Петербург'},
        { value: 'nsk', label: 'Новосибирск'},
        { value: 'kzn', label: 'Казань' }
      ]
    }
  }
})