Which of the following is a dial-up WAN connection type?

ISDN, or Integrated Services Digital Network, qualifies as a dial-up WAN connection type because it is designed to transmit voice, video, and data over traditional telephone lines. ISDN provides digital dial-up communication, allowing users to connect to a wide area network using standard phone lines but at a higher quality and speed compared to analog modems.

In contrast, DSL (Digital Subscriber Line) uses existing telephone lines for high-speed internet access but is considered a broadband connection rather than a dial-up type. Fiber optic connections are fundamentally different, as they use light to transmit data over fiber cables, providing extremely high speeds that far exceed any dial-up capability. Satellite connections involve data transmission via satellites, which is also not classified as dial-up due to its specific technology and capabilities.