JSFiddle - React, Tailwind, and code Playground
HTML
<select class="form-control square" id="subCategory" name="Category">
</select>
JavaScript
var data = {"1": "Android", "2":"IOS", "3":"Business Management Systems", "4":"Database", "5":"Codes/Scripts", "6":"Others"};
console.log( data );
$.each(data, function(key, value) {
$('#subCategory').append(
$('<option/>').val( key ).text( value )
);
});