Class B Shares
  
Like Class A shares, except they, uh...didn't study as hard. But as a trade-off, they probably had more fun on the weekends.
Different classes of stock have different levels of control within companies. Usually, Class A shares will have more voting rights than Class B shares.
So one person owns 100 shares of Class A stock. Another person owns 100 shares of Class B. They both have an economic stake in the company. But (in the typical situation), the Class A investor will have more control over what goes on at the company. Their votes count for more at shareholder meetings, even though the two people nominally hold 100 shares each. Those Class A shares get more votes.