Final answer:
The issue is most likely related to an incorrect default gateway setting on the new computer, which restricts it from communicating with hosts on different subnets. So, the correct option is B) Default gateway.
Step-by-step explanation:
When a new computer can communicate with hosts on the same subnet but not with those on a different subnet and static IP addressing is used, the issue is most likely related to the default gateway. This setting is used by devices to access networks beyond their local subnet.
If the subnet mask were incorrect, it likely wouldn't be able to communicate with hosts on the same network at all. The DNS server is important for resolving domain names to IP addresses but would not affect communication with other subnets directly. The hostname would not affect networking at the IP level. The default gateway is essentially the door through which a computer sends information to devices on other networks. It must be correctly configured to ensure that the computer can reach out beyond its immediate network.