Final answer:
Developers may manage system resources themselves rather than depending on the OS for better control and to optimize application performance based on specific requirements that the OS might not take into account.
Step-by-step explanation:
The question poses a fundamental issue in computer science: the balance between letting an operating system (OS) manage resources and allowing developers to manually handle these tasks. While OSs are designed to provide a generalized solution for resource management, they may lack the specificity required for optimal performance of certain applications. This is why not letting the OS handle memory and disk management can be advantageous.
Option b) 'Developers have better control over system resources' is often a key reason. Developers can fine-tune application performance by managing resources according to the unique needs of their applications that the OS might not be aware of. Option d) 'OS lacks knowledge of specific application requirements' also holds true, suggesting that a one-size-fits-all approach may not be ideal for applications with unique or demanding resource requirements.