I have a question regarding punctuation. Please consider the following sentence:
In 2010, he became CEO of the company [punctuation?] a position he still holds today.
I'm wondering which punctuation is correct/acceptable/incorrect and why:
- Comma?
In 2010, he became CEO of the company, a position he still holds today.
- Semicolon?
In 2010, he became CEO of the company; a position he still holds today.
- Parentheses?
In 2010, he became CEO of the company (a position he still holds today).
- Em dash?
In 2010, he became CEO of the company — a position he still holds today.
Thank you.