A D-shaped 25-pin female port on the back of a computer is a:

The D-shaped 25-pin female port is identified as a parallel port. This type of port was commonly used in older computers for connecting printers and other peripheral devices. It allows data to be sent and received simultaneously, which is a characteristic of parallel communication.

The design of the port, being D-shaped with 25 pins, fits the specific configuration of parallel ports, which were prevalent before USB became the standard for device connections. These ports were typically used for connecting a printer and had a maximum data transfer rate that was adequate for many tasks at that time.

Additionally, other ports like USB and HDMI have distinctly different shapes and pin configurations, which do not match the D-shaped design of the parallel port. USB ports are usually rectangular, while HDMI ports have a larger, flatter shape. PS/2 ports, used primarily for connecting keyboards and mice, are smaller, circular ports with fewer pins. Thus, the architecture of the D-shaped 25-pin female port points directly to its identification as a parallel port.