Firmware is a specific class of computer software that provides low-level control for a device's hardware. It is stored in non-volatile memory chips like Read-Only Memory (ROM), EPROM, or flash memory. When a device is powered on, the processor begins executing the firmware instructions to perform hardware initialization, conduct self-tests (like POST), and load the operating system or higher-level application software into main memory. This boot-up process is fundamental to making the device operational.

B. Application: Application software is designed for end-user tasks and runs on an operating system, not for initializing the core hardware from ROM.

C. Container: A container is a virtualization technology that packages an application and its dependencies; it is not low-level initialization software.

D. Service: A service is a background process that provides functionality to other programs, which is distinct from the initial firmware that boots the hardware.

1. Patterson, D. A., & Hennessy, J. L. (2017). Computer Organization and Design: The Hardware/Software Interface. Morgan Kaufmann. In Chapter 1, Section 1.4, the text discusses the role of the Basic Input/Output System (BIOS), a type of firmware, which is "stored in a ROM" and is "used to initialize the hardware."

2. Koopman, P. (1997). Embedded System Design. Carnegie Mellon University, 18-348 Courseware. Lecture 1, "Introduction to Embedded System Design," Slide 11. The lecture defines firmware as "software stored in ROM" and distinguishes it from software loaded from a disk.

3. MIT OpenCourseWare. (2012). 6.828 Operating System Engineering, Fall 2012. Lecture 2: The Boot Process. The lecture notes describe how the BIOS, a form of firmware residing in ROM, is the first software to run to "set up the hardware" before loading the operating system.