如何使用PHP获取从curl POST返回的JSON响应的一部分

$curl = curl_init();

$url = "https://example.com/api";
$data = array(
    "key1" => "value1",
    "key2" => "value2"
);
$options = array(
    CURLOPT_URL => $url,
    CURLOPT_POST => true,
    CURLOPT_POSTFIELDS => json_encode($data),
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => array(
        'Content-Type: application/json',
        'Authorization: Bearer token'
    )
);
curl_setopt_array($curl, $options);

$response = curl_exec($curl);

curl_close($curl);

$jsonData = json_decode($response, true);
$desiredPart = $jsonData['desired_key'];