The correct answer is C. Interregnum.
An interregnum is a period of time between the end of one reign and the beginning of another. The word comes from the Latin words “inter” meaning “between” and “regnum” meaning “kingdom”.
The word “interregnum” is often used to describe a period of political instability or uncertainty. For example, the English Civil War was followed by a period of interregnum between the execution of Charles I and the restoration of Charles II.
The word “interregnum” can also be used to describe a period of time between the end of one thing and the beginning of another. For example, the interregnum between the end of one school year and the beginning of the next.
The other options are incorrect because they are not the correct spelling of the word “interregnum”.