If Mary doesn't use the credit card in a responsible way, she will not have control of her expenses and may use up all the credit limit set by her parents? This will cause her being barred from using the card for more important needs. This may affect the use of the principal cards also.
United States and the United Kingdom would use the preponderance of their resources to subdue Nazi Germany in Europe first. Simultaneously, they would fight a holding action against Japan in the Pacific, using fewer resources.