The question specifies the use of a "bottom-up" troubleshooting methodology. This approach requires starting at the lowest layer of the OSI model, which is Layer 1 (the Physical Layer), and systematically working up through the layers. For a wireless IoT device, this means first verifying physical aspects like power status, antenna integrity, and the radio frequency (RF) environment (e.g., signal strength, interference). Only after confirming the physical layer is functional would the troubleshooter move to Layer 2 (Data Link), Layer 3 (Network), and so on, until the source of the problem is isolated.

B. Layer 4: Starting at the Transport Layer (TCP/UDP) violates the fundamental principle of the bottom-up method, which mandates beginning at Layer 1.

C. Layer 5: The Session Layer is a higher layer; beginning troubleshooting here would skip the foundational physical, data link, network, and transport layers.

D. Layer 6: The Presentation Layer is even higher in the OSI stack, making it an incorrect starting point for a bottom-up investigation.

---

1. Cisco Systems, Inc., "Troubleshooting IP Connectivity." Cisco Technical Support & Documentation. This document outlines standard network troubleshooting methodologies. It states, "The bottom-up approach to troubleshooting starts with the physical components of the network and moves up the OSI model... This approach is methodical and is the best way to find the cause of a problem that is not obvious."

2. Forouzan, B. A., "Data Communications and Networking," 5th Edition. McGraw-Hill Education. In chapters discussing network management and troubleshooting, the text describes the layered model approach, where the bottom-up method begins at the physical layer (Layer 1) to check the transmission medium and physical connectivity first. (Refer to Chapter 1, Section 1.3 "The OSI Model" and general troubleshooting principles in network management sections).

3. University of Pittsburgh, School of Computing and Information, Course: TELCOM 2125 Network Management and Security. Lecture notes on "Network Troubleshooting" describe the bottom-up approach as starting at Layer 1 of the OSI model to verify physical connectivity before proceeding to higher layers. This is presented as a standard, systematic methodology for fault isolation.