QUESTION # 5 [05+05-10 Marks a. What are the different types of NoSQL databases? How do I read a firebase Realtime database? Explain with example code. [05 Marks] b. Firebase rules provides a way to identify user role while performing read and write operations. These rules will acts a security layer on the server before perform any CRUD operation. By default the rules allows user to perform read & write operation only after authentication. The below rules allow authenticated users only to read or write data. 105 Marks "rules" : { ".read": "auth != null", ".write": "auth != null" } ) Write a rules to validate the username to be less than 50 chars , mobile number and email to be valid using email regular expression