Is Object.GetHashCode() unique to a reference or a value?

Question

The MSDN documentation on Object.GetHashCode() describes 3 contradicting rules for how the method should work.

1. If two objects of the same type represent the

Answer 1

By default it does it based on the reference to the object, but that means that it's the exact same object, so both would return the same hash. But a hash should be based on the value, like in the case of the string class. "a" and "b" would have a different hash, but "a" and "a" would return the same hash.