Consider the following two statements. $$S_1 : \quad \text{Destination MAC address of an ARP reply is a broadcast address.}$$ $$S_2 : \quad \text{Destination MAC address of an ARP request is a broadcast address.}$$ Which one of the following choices is correct?

Let us analyze both statements regarding the Address Resolution Protocol (ARP):

1. ARP Request ($S_2$): When a host needs to find the hardware (MAC) address corresponding to a known IP address, it sends an ARP request frame. Because it does not know which host has that IP address, the request is sent to the broadcast MAC address (FF:FF:FF:FF:FF:FF) so that all hosts on the local network segment receive it. Hence, the destination MAC address of an ARP request is a broadcast address. Therefore, statement $S_2$ is true.

2. ARP Reply ($S_1$): The target host responds with an ARP reply containing its MAC address. Since the target host already obtained the source's MAC address from the request frame, the reply is sent directly to the requester as a unicast frame. Hence, the destination MAC address of an ARP reply is a unicast address, not a broadcast address. Therefore, statement $S_1$ is false.

Thus, $S_1$ is false and $S_2$ is true, which corresponds to option (C).