magento2 get all customizable option from products

create test file in root directory and place the below code excute it with domain/test.php

<?php

    //THis is test

    echo '<pre>';
    error_reporting(0);
    ini_set('display_errors', 1);

    use Magento\Framework\App\Bootstrap;

    include('app/bootstrap.php');
    $bootstrap = Bootstrap::create(BP, $_SERVER);
    $objectManager = $bootstrap->getObjectManager();
    $url = \Magento\Framework\App\ObjectManager::getInstance();
    $storeManager = $url->get('\Magento\Store\Model\StoreManagerInterface');
    $websiteId = $storeManager->getWebsite()->getWebsiteId();
    $state = $objectManager->get('\Magento\Framework\App\State');
    $state->setAreaCode('frontend');
    //$product = $objectManager->get('\Magento\Catalog\Model\Product')->load('2331');

    $productCollection = $objectManager-     >create('Magento\Catalog\Model\ResourceModel\Product\Collection');
    /** Apply filters here */
    $collection = $productCollection->addAttributeToSelect('*')
            ->load();
    foreach ($collection as $product) {
        //echo 'Name  =  '.$product->getName().'<br>';
        $customOptions = $objectManager->get('Magento\Catalog\Model\Product\Option')->getProductOptionCollection($product);
        //print_r($customOptions->getData());
        foreach ($customOptions as $option) {
            $values = $option->getValues();
            //print_r($option->getTitle());
            if (empty($values)) {
                echo $product->getName() . "===" . $product->getSku() . "===" . $option->getOptionId() . "===" . $option->getDefaultTitle() . "===" . "no options" . "<br />";
                ;
            } else {
                foreach ($values as $value) {
                    //print_r($value->getTitle());
                    echo $product->getName() . "===" . $product->getSku() . "===" . $option->getOptionId() . "===" . $option->getDefaultTitle() . "===" . $value->getTitle() . "===" . $value->getPrice() . "<br />";
                }
            }
        }
        //die("here");
    }
?>