Correct Answer: Professional

Solution : The fourth option is the correct choice.

An amateur is a person who is incompetent at a particular activity. A professional is a person who is highly skilled, trained, or qualified in a specific field or occupation.

The meanings of the other options are as follows:

• Hobbyist : someone who pursues a particular activity or interest for pleasure.
• Devotee : A person who is deeply committed to a particular cause or belief.
• Layman : A person who lacks specialised knowledge or expertise in a particular field.