A user reports that they cannot get their laptop to work with a video projector connected with an HDMI cable. The projector is turned on. The HDMI cable is securely connected on both ends, and the laptop displays properly on its own screen. The display mode is set to "Duplicate" on the laptop. Which of the following is most likely causing the issue?

The scenario describes a situation where the physical connections and the laptop's display settings are confirmed to be correct. The most common cause for a projector not displaying an image under these circumstances is a configuration error on the projector itself. Projectors often have multiple input ports (e.g., HDMI 1, HDMI 2, VGA). The user must manually select the correct active input source using the projector's remote or on-device controls to match the physical port where the HDMI cable is connected.

A. The presence of an HDMI port and the ability to connect the cable makes it unlikely the projector does not support HDMI at all.
B. "Duplicate" mode is a valid setting for mirroring the laptop screen. While "Extend" is another option, "Duplicate" not working points to a connectivity or source issue.
C. While a port failure is possible, it is a hardware fault. Standard troubleshooting methodology dictates checking simple configuration issues, like the input source, before assuming hardware failure.

1. Dell Inc. (2023). How to Troubleshoot Dell Projector issues. Dell Knowledge Base, Article ID: 000125849. In the troubleshooting steps for "No Video," the guide explicitly lists "Check if the correct input source is selected on the projector (HDMI, VGA, S-video, Composite, and so on)."

2. Epson. (2022). Projector User's Guide - PowerLite Series. In the "Troubleshooting" section for "No image is projected," a primary solution provided is "Press the [Source Search] button on the projector or remote control to select the correct input source."