Final answer:
Ariana made an oral promise to give Cassie money, but since the agreement wasn't in writing, it is not enforceable. Therefore, Ariana is allowed to change her mind. The correct answer is A) Agreement wasn't in writing.
Step-by-step explanation:
The correct answer is A) The Agreement wasn't in writing.
Based on the given scenario, Ariana made an oral promise to Cassie to give her $10,000. However, since the agreement wasn't in writing, it is not enforceable. In contract law, to be enforceable, certain types of agreements, such as those involving a significant amount of money, must be in writing.
In this case, Ariana had a change of heart on the way to the bank, and she is allowed to do so because the initial agreement was not in writing. Therefore, Ariana is not legally obligated to give Cassie the money. The correct answer is A) Agreement wasn't in writing.