A technician needs to replace a laptop's display assembly.

Laptop display assemblies typically include not only the LCD panel but also the webcam, microphone, display cable, and critically, the Wi-Fi antennas. In most laptops, Wi-Fi antennas are built into the display bezel, because the elevated position allows for stronger wireless signal reception. When replacing the entire display assembly, the antennas must be carefully disconnected and reconnected during reinstallation.

CompTIA A+ emphasizes proper cable routing and antenna reattachment as essential steps in laptop hardware disassembly and reassembly. Failing to reconnect these antennas results in weak or nonfunctional wireless connectivity, even though the display replacement itself may be successful.

Heat sinks and CPU fans are located on the motherboard and are unrelated to display assembly replacement. Resetting BIOS settings is unnecessary unless troubleshooting firmware-related issues, not replacing hardware components like a display. Therefore, the only action that aligns with standard laptop design and CompTIA A+ procedures is ensuring that the wireless antennas are reconnected.

Thus, the correct answer is B.