Okay, I need to classify this bug report: "Cannot use usb-host on Mac OS". Let's see. First, looking at the options: device, graphic, socket, network, KVM, boot, vnc, debug, files, permissions, performance, kernel, peripherals, hypervisor, and others like mistranslation or assembly. The issue is about USB host not working on macOS. USB-host relates to hardware devices. In QEMU, the USB host device emulation would be part of device handling. So it's under 'device' category. Wait, but another thought: sometimes USB issues can be related to peripherals more specifically. But since 'device' is a broader category that includes all types of hardware devices, including USB, I think 'device' is correct. The bug report deals with the inability to use USB host functionality on macOS, which falls under device handling in QEMU. **Step-by-Step Explanation:** 1. **Identify Keywords:** The main issue is about "usb-host" and its failure on Mac OS. 2. **Understand Context:** In QEMU, usb-host relates to emulating a USB host for devices. 3. **Categorize Issue:** This falls under device-related problems as it's about hardware emulation. **Answer:** device