Please explain why I am able to instantiate the “Application” interface in Excel VSTO

Question

I have the following C# code in my application which works just fine. It launches a new instance of Excel.

private readonly Microsoft.Office.Interop.Excel.A         


        

Answer 1

Because MSDN says so:

For example, the following code uses the Excel Microsoft.Office.Interop.Excel.Application interface. At run time, it uses the Application class to instantiate an Excel Application object and open a worksheet.