Which protocol is used for secure remote access to network devices?

Correct answer: SSH

Option C is correct: SSH (Secure Shell) provides encrypted, authenticated remote access to network devices and is the industry standard replacement for insecure legacy protocols. Option A is incorrect because HTTP is an unencrypted application-layer protocol for web traffic and provides no secure remote shell capability. Option B is incorrect because FTP (File Transfer Protocol) is used for file transfers and transmits credentials in plaintext, making it unsuitable for secure remote device management. Option D is incorrect because Telnet transmits all data, including passwords, in cleartext, making it vulnerable to interception and unsuitable for secure remote access.