What purpose does the Point-to-Point Protocol (PPP) serve?

The Point-to-Point Protocol (PPP) is specifically designed to establish a direct connection between two networking nodes. Its primary function is to enable the transmission of data over various types of physical connections, particularly over serial cable, phone lines, or fiber optic links. This makes it an essential protocol for dial-up internet connections, facilitating communication between a user's computer and an Internet Service Provider (ISP).

PPP supports multiple network layer protocols, which means it can transmit both IPv4 and IPv6 traffic, along with offering features such as authentication, encryption, and compression. Its capability to connect computers over a phone line is particularly important in scenarios where dedicated lines or broadband services are not available, making it an effective tool for remote access networking.

The other options do not align with the defined purpose of PPP. Creating web pages, managing electronic files, and sending email messages involve different protocols and services that are not related to the establishing or maintaining of point-to-point connections for data transmission. Therefore, the option highlighting the connection of computers over a phone line accurately reflects the primary use of PPP.