Final answer:
The best technology for transmitting messages securely during website development is HTTPS, as it encrypts data exchanged between a browser and a website, protecting sensitive information.
Step-by-step explanation:
When developing a website and ensuring that certain messages are transmitted securely, the most appropriate technology to use is HTTPS (Hypertext Transfer Protocol Secure). This protocol encrypts data between the user's browser and the website, protecting sensitive information such as login credentials, personal information, and payment details from being intercepted by unauthorized parties. HTTPS incorporates TLS (Transport Layer Security) to provide a secure channel, whereas HTTP does not offer encryption. S-HTTP (Secure Hypertext Transfer Protocol) was an alternative for encrypting individual messages, but it is not widely used. SET (Secure Electronic Transaction) was designed to secure electronic transactions, specifically credit card payments, but it has mostly been replaced by other secure payment technologies.