What are the most important on-page SEO elements?

What are the most important on-page SEO elements?

  A)  Page title, URL, meta description, content, and page header

  B)  Page title, meta description, meta keywords, content and page headers

  C)  Page title, URL, meta description and meta keywords

  D)  Page title, URL, meta description, content and internal links

  E)  The Fundamentals of Blogging