A little background
Mario's first appearance came with the original Donkey Kong in 1981, since then the Mario franchise has sold over 879 million copies, with "Super Mario" titles making up 430 million of that. Other major selling games that are considered part of the Mario franchise include the Mario Kart series (181 million copies), Mario Party (69 million), and Mario Sports (46 million).
Not listed in the possible answers, but Tetris is the second best-selling game franchise with roughly 495 million sales, courtesy of its popularity as a download among mobile phone owners.
In third place with about half as many unit sales as Mario, some 480 million copies of Pokémon have been sold since the 1996 Japanese release of the original Pokémon RPG for Game Boy.
Activision blockbuster Call of Duty has sold an impressive 425 million copies over the years, thanks to its yearly release cycle with excellent sales figures year in and year out. Call of Duty is also the best-selling first-person shooter game and top game franchise created in the United States.
Grand Theft Auto has roughly matched Call of Duty sales though, tied at 425 million for the fourth/fifth spots. Although the shooter is on a yearly release cycle, GTA is a huge blockbuster with only a handful of games released in the franchise's history.
Madden NFL (130 million copies) has been around since 1988 and is surprisingly far down the list behind The Sims, Need for Speed, Assassin's Creed, Final Fantasy, as well as Minecraft and FIFA.