Which best describes the content marketing and inbound marketing relationship?

Google Adwords, Analytics Certifications
Which best describes the content marketing and inbound marketing relationship?

A) Both are valuable and take a lot of time and work. It’s best to focus your time on one or the other.
B) If you do both then you’ll be competing with yourself.
C) A great content marketer doesn’t need to do inbound marketing.
D) Success relies on both as each serves a different function