What is the difference between these three ways to clear a Textbox?

Question

I am bit confused between the below three ways to clear the contents of a textbox. I am working with WPF and found All are working, but I am unable to find the difference.

Answer 1

Some say String.Empty is faster than "" however String.EMpty is Static member that is initialized to ""

When we call String.Empty the IL makes call to

mscorlib.dll 

IL_0007:  ldsfld     string [mscorlib]System.String::Empty

Whereas for "" it does not

IL_001a:  ldstr      ""

SO logically it would make more sense that "" is more efficient than String.Empty