var sample = "Hello World";
The actual type is determined at compilation time, and has no impact on the runtime
The actual type is determined at runtime, and late binding takes effect.
"var" itself is a specific type defined by the framework, and no special binding takes place
It is important to understand that the var keyword does not mean "variant" and does not indicate that the variable is loosely typed, or late-bound. It just means that the compiler determines and assigns the most appropriate type. Useful resources, Implicitly Typed Local Variables