Final answer:
The correct answer is option (a) Check the DNS configuration for the local machine.
Step-by-step explanation:
When facing the error "SSH could not resolve hostname", checking the DNS configuration (a) is critical as it helps determine whether the DNS resolution process is at fault. If DNS settings are correct, using an IP address (b) or restarting DNS services (c) are alternatives.
When you encounter the error "SSH could not resolve hostname, temporary failure in name resolution", it indicates that SSH is unable to translate the hostname you've provided into an IP address. This is typically due to a problem with Domain Name System (DNS) resolution. Before going further, confirming the DNS settings on your local machine is a crucial troubleshooting step. Configuration files such as /etc/resolv.conf on Unix-based systems or settings within the networking interfaces on Windows should be the first places to check. If the DNS configuration seems correct and the problem persists, you might consider option (b) using an IP address instead of a hostname, which bypasses DNS resolution altogether.
If direct usage of an IP address works, this confirms the issue is indeed with DNS resolution. Only if these steps fail should you consider restarting DNS-related services with option (c), and reinstalling the OpenSSH client (option (d)) should be a last resort, unlikely to resolve a DNS issue.