Final answer:
An Industrial-organizational psychologist is the professional best suited to assist employees in adjusting to company downsizing and reorganization.
Step-by-step explanation:
Liz, as the CEO of a major company facing downsizing and reorganization, is likely to seek the expertise of an Industrial-organizational psychologist. These professionals are adept in aiding employees through transitions such as downsizing, ensuring that both the retained and laid-off employees receive appropriate support. An Industrial-organizational psychologist's role includes managing employee reactions, helping to maintain job satisfaction, and fostering a positive organizational culture during challenging times like corporate restructuring.