Answer:
a. Their contributions to an organization are based on their expertise.
Step-by-step explanation:
Knowledge workers can be described as workers whose main requirements for their jobs is to think for a living. They are usually experts in different fields like science, engineering, accounting, etc.
Knowledge workers are expected to use their expertise to bring about innovations, and also to always suggest with new and better ways of doing things.
Therefore, knowledge workers' contributions to an organization are based on their expertise.