Error in v-on handler: TypeError: Cannot use in operator to search for in null

<div :v-for="option in this.options">
   <div v-if="option" class="option mt-4">
       {{ option }}
   </div>
</div>

You have to fix the following:
1. Change :v-for to just v-for
2. Remove this. from this.options because you only should use this. in the 
script area
3. Put this whole block inside another <div> because there should be only 1 
element inside <template> tag. So since you're using a loop, multiple elements
will be rendered