Answer:The Three amigos namely,
-> James Rumbaugh (OMT): A veteran in analysis who came up with an idea about the objects and their Relationships (in particular Associations).
-> Grady Booch: A veteran in design who came up with an idea about partitioning of systems into subsystems.
->Ivar Jacobson (Objectory): The father of USECASES, who described about the user and system interaction.