Why class containing extension method needs to be static ?

Question

As we understand that when we create extension method on any type we create it as static method. But class containing this extension method is also needs to be static otherwise we get compile time error. I didn't get proper answer for this why this class should be static in this case? Only for accessing static method we don't need static class. That we can de even if class is non-static i.e. we can access that static method by ClassName.MethodName(). But why this class is to be static in this case? Can someone please answer this?

Hassan Uddin Mughal · Answer

Basically extension methods are designed to make LINQ work. LINQ only needs extension methods in static non-generic non-nested classes to work. Things that did not contribute to making LINQ work was cut. If you have a scenario where extension methods would be useful in generic nested and non-static classes then I would like to take a look on that scenario.