Answer:
A. Enhancing and increasing one's skill set
Step-by-step explanation:
Advancement of one's career is dependent on what one has to offer to the organization towards the achievement of set goals. It is ordinarily expected that the goals of an organization are usually set by the top management and cascaded down to employees.
What determines who gets into top management are the skills (which may be influenced by the years of experience) being offered.
The more a person can do, the higher the responsibilities given to that person.
As such, the right option is A. Enhancing and increasing one's skill set.