Final answer:
The number of active DHCP clients on the network depends on the subnet mask being used. A subnet mask of 255.255.255.0 allows for a maximum of 254 active DHCP clients on the network.
Step-by-step explanation:
In order to determine how many active DHCP clients can be on the network at the same time, we need to look at the subnet mask being used. The subnet mask determines the number of available IP addresses in a network. Based on the given options (a, b, c, d), the answer would be option d. A subnet mask of 255.255.255.0, which is commonly used, allows for a total of 254 usable IP addresses. This means that there can be a maximum of 254 active DHCP clients on the network at the same time.