CI Financial interview question

1.Asked me intro about myself (experience) 2.Since I have experience in .NET, asked what is diff between .NET framework and .NET core 3.What is WCF and WPF 4.Polymorphism 5.What is delegate and uses of delegates 6.How to build ASP.NET application 7.What is XAML 8. What is full form of PHP 9.diff between PHP and .NET (advantages and disadvantages of both) 10.What is API 11.What is REST API 12.What is Web service 13. Write a query to get how many installments the payment for customers is completed and how many outstanding payment is still pending based on 2 tables.