Which of the following is NOT one of the main characters in Grand Theft Auto V’s story mode?

The answer is Tommy Vercetti because he is not one of the main characters in Grand Theft Auto V's story mode. While Tommy Vercetti is a prominent character in the game Grand Theft Auto: Vice City, set in the 1980s, he is not present in the storyline of Grand Theft Auto V, which takes place in a different fictional location and follows the lives of three different protagonists: Michael De Santa, Franklin Clinton, and Trevor Philips. Therefore, Tommy Vercetti is not included as one of the main characters in Grand Theft Auto V's story mode.