Answer:
D. a penalty clause.
Explanation:
A penalty clause -
The clause is usually mentioned in some specific contracts ,
The clause enables one of the party ( usually the weak one ) , to get compensation during the breach of contract , as in most of the cases the situation get downs very costly fight between the parties , hence in order to avoid this condition , a penalty clause is usually inserted in the contract .
The penalty clause can be unenforceable , if the requirements are not fulfilled , hence need to be aware before making the contract .
Hence , from the given scenario of the question ,
The correct option is , D) a penalty clause.