What is the “content golden rule?”

What is the “content golden rule?”
  A)  The Law of Diminishing Returns: don’t add more information or design into your content than is necessary.
  B)  The 80/20 Rule: 80% of your content should be customer-focused, 20% of your content should be sales-related.
  C)  The Cocktail Party Rule: don’t just talk about yourself, involve others, as well.
  D)  The Frequency Rule: publish content at least 2 times a week.