Final answer:
When Cassie orders a bikini from Moana Bikini, she enters into an executory contract, as both parties have obligations to perform that have not been completed yet.
Step-by-step explanation:
When Cassie orders a new bikini from Moana Bikini, the two parties enter into a contract. The contract is an agreement between buyer and seller that creates mutual legal obligations. The type of contract in question is an executory contract.
An executory contract is a contract under which not all obligations have been performed by one or both parties. Since Cassie has likely placed the order but has not yet received the bikini, and Moana Bikini has accepted the order but has not yet delivered the bikini, the contract still requires certain actions to be completed. Therefore, the correct answer is B. Executory contract.