Final answer:
Restricting a child process to a subset of resources prevents the system from being overloaded by the creation of too many sub-processes.
Step-by-step explanation:
Restricting the child process to a subset of the parent's resources prevents any process from overloading the system by creating a lot of sub-processes. This is a common practice in computer systems to ensure stability and proper resource management. By limiting the amount of resources that a child process can use, such as CPU time, memory, and number of concurrent processes, the system prevents single applications from consuming too much of the system's resources which could lead to performance degradation or a system crash.
In contrast, options a), b), and d) don't directly relate to the concept of restricting resources, as they mention secondary storage usage, CPU utilization, and utilizing multiple resources, respectively. However, these could also be aspects of resource management in the broader sense that systems need to handle to maintain overall system health and efficiency.