Answer:
The correct answer will be profess.
Step-by-step explanation:
A professional is a person who is skilled and have knowledge about a particular activity or subject through which he earns for living.
The profession word was used for the first time in history as "profess" for the people who were more specialized in their trade, to profess their skills to others but the use of this word profess declined after the late 1800s and the word professional gained after that.
Thus, profess is the correct answer.