The command sudo nmap -script=bro* -e ethO is the best choice for establishing a baseline of all IPv4 network traffic on the local VLAN without a local IP address. The -script=bro* specifies the use of scripts that can capture and analyze traffic, and -e ethO specifies the network interface to be used. This allows the vulnerability assessor to capture and analyze network traffic at a low level, which is essential for baseline analysis. References: * Nmap Scripting Engine (NSE) * Nmap Network Interface Specification