Which of the following methods will allow data to be sent on the Internet in a secure format?

A Virtual Private Network encrypts all traffic passing through it using protocols such as IPsec, SSL/TLS, or L2TP, creating a secure tunnel over the public internet. This ensures confidentiality and integrity of data in transit. VPNs are the standard solution for securely transmitting data across untrusted networks like the internet.

Serial Line Interface Protocol (SLIP) is a legacy data link layer protocol for serial connections that provides no encryption or authentication, making it unsuitable for secure transmission.

Browsing alone does not secure data in transit - without an additional encryption layer such as HTTPS/TLS, data sent during a browsing session is transmitted in plaintext.

Point-to-Point Protocol (PPP) is a data link layer encapsulation protocol used for direct connections that does not provide encryption by default and is not designed for secure internet data transmission.