The correct answer is the Immunity debugger. This tool is specifically designed for interactive debugging and is commonly used for malware analysis and exploit development due to its ability to manipulate running processes and probe the internals of an application in real-time. It provides cybersecurity professionals with deeper insights into how an application behaves under certain conditions, potentially revealing exploitable vulnerabilities. Other options like WireShark, Nessus, and GDB have different primary uses; WireShark is a network protocol analyzer, Nessus is a vulnerability scanner, and GNU debugger (GDB) is more general-purpose and less specialized in malware analysis or exploit development than Immunity debugger.