Which of these is NOT a main playable character in "Grand Theft Auto V"?

The answer is Lamar. Lamar is not a main playable character in Grand Theft Auto V because although he plays a significant role in the game's storyline as a friend and associate of the main protagonist Franklin, he is not controllable by the player during gameplay. While players do interact with Lamar in various missions and activities, the main playable characters in Grand Theft Auto V are Michael, Franklin, and Trevor.