Solution :
a). In the context, Jim received $ 275 for the car repairing services form some member from the club. In this exchange of the services, an income is been received in amount of a value of the services received ( the gross income includes receipt of the services and also the money and goods). Therefore, Jim is being taxed on an amount of $275 for the car repair services.
b). The issue in this case is whether a "credit" represents the valuable right. As the right can be redeemed for the that is property worth of $150, then under the constructive receipt, Jim must recognize an income of $150.
c). Jim received an credit of $450 to be applied for the next year. If the credit can be redeemed or used for any future services, the taxpayer then can argue that the realization has not yet occurred. But, it has be included in Jim's gross income for the next year when his credit amount becomes the valuable right.