Wix code SDK Warning

I keep getting this error in my code and I have no idea what is wrong with it. I am making 3 dropdown menus that filter between each one. Help please!
Error message: Wix code SDK Warning: The selectOption parameter at index 13 that is passed to the options function cannot be set to [object Object]. Options must contain either a non-null value or a non-null label.

import wixData from ‘wix-data’ ;

$w.onReady( function () {

uniqueDropDown1(); 

});

function uniqueDropDown1 (){

wixData.query( "countiesList" ) 

    .limit( 1000 ) 

  .find() 

  .then(results => { 

const uniqueTitles = getUniqueTitles(results.items);

        $w( "#dropdown1" ).options = buildOptions(uniqueTitles); 

  }); 

function getUniqueTitles(items) {

const titlesOnly = items.map(item => item.county);

return [… new Set(titlesOnly)];

} 

function buildOptions(uniqueList) {

return uniqueList.map(curr => {

return {label:curr, value:curr};

    }); 

} 

}

export function genre_change(event, $w) {

uniqueDropDown2();

$w( “#dropdown2” ).enable();

}

function uniqueDropDown2 (){

wixData.query( "countiesList" ) 

    .contains( "county" , $w( "#dropdown1" ).value) 

    .limit( 1000 ) 

  .find() 

  .then(results => { 

const uniqueTitles = getUniqueTitles(results.items);

       $w( "#dropdown2" ).options = buildOptions(uniqueTitles); 

  }); 

function getUniqueTitles(items) {

const titlesOnly = items.map(item => item.subCounty);

return [… new Set(titlesOnly)];

} 

function buildOptions(uniqueList) {

return uniqueList.map(curr => {

return {label:curr, value:curr};

    }); 

} 

}

export function subcategory_change(event, $w) {

uniqueDropDown3();

$w( “#dropdown3” ).enable();

}

function uniqueDropDown3 (){

wixData.query( "countiesList" ) 

    .contains( "subCounty" , $w( "#dropdown2" ).value) 

    .limit( 1000 ) 

  .find() 

  .then(results => { 

const uniqueTitles = getUniqueTitles(results.items);

       $w( "#dropdown3" ).options = buildOptions(uniqueTitles); 

  }); 

function getUniqueTitles(items) {

const titlesOnly = items.map(item => item.ward);

return [… new Set(titlesOnly)];

} 

function buildOptions(uniqueList) {

return uniqueList.map(curr => {

return {label:curr, value:curr};

    }); 

} 

}

the specific lines of code with the problem is: $w( " #dropdown1 " ).options = buildOptions(uniqueTitles); });

can you fix it?