Using | and & operators with the bool? type

The results of these operators are listed in the following table: true & null = null; true | null = true; false & null = false; false | null = null; null & null = null; null | null = null.

The null-coalescing operator (??)

The null-coalescing operator has the following form: first_operand ?? second_operand; The operator returns the first_operand if it is not null; otherwise, it returns the second_operand.

Links:

Boolean Data Type

Using Nullable Types