What is false about C# Nullable<_T_> types

C# Nullable<T> or T? are nullable types that can be assigned a value or null. All value types can be declared as Nullable<T> types. Reference types cannot be declared Nullable<T> types because they are already nullable. These are some examples of Nullable<T>:

int? i = 5;
bool? b = null; 

Which one of following statements is false about Nullable<T> types?