A defined benefit scheme promises a specific income upon retirement whereas, with a defined contribution scheme, the income depends on factors such as the size of monthly contributions and investment performance. Defined benefit schemes, as the name suggests, offer a 'defined' or 'fixed' benefit upon retirement. This benefit is usually calculated based on the employee's salary and years of service. The employer bears the investment risk in this type of scheme, as they are obligated to provide the promised benefit regardless of the performance of the underlying investments. On the other hand, in a defined contribution scheme, both the employee and the employer contribute to the employee's individual account. The final benefit upon retirement depends on the total contributions made and the performance of the investments. Therefore, the investment risk in this type of scheme is borne by the employee. The key difference between the two schemes lies in who bears the investment risk and how the retirement benefit is determined.\n\nChoice A is incorrect. Both defined benefit schemes and defined contribution schemes can be employer-sponsored. The key difference lies in the structure and benefits, not in who runs the scheme.\n\nChoice B is incorrect. The duration of both defined contribution and defined benefit schemes can vary depending on the specific terms set by employers or plan administrators, not necessarily limited to 40 work-years for defined contribution schemes.\n\nChoice C is incorrect. Both types of pension plans have tax implications, but their tax-deductibility does not distinguish them from each other. In many jurisdictions, contributions to both types of plans are tax-deductible up to certain limits.