A good notification:

• It is relevant
• It delivers in the background
• It can be dismissed
• It has a default action

Correct answer is

• It is relevant

Explanation: Push notifications are one of the most valuable capabilities of native apps, and this capability is now available on the web. To get the most out of them, notifications need to be timely, precise, and relevant.
Read more here: https://support.google.com/partners/answer/7336533