Momentum is a vector, although we don't hammer on that. In order to completely describe a momentum, you need a magnitude AND a direction ... just like force and velocity.
So choice #2 is the magnitude of a momentum, without its direction.
Choice #3 is the full package, with both the magnitude and the direction.
Choice #1 has units of energy, and choice #4 has units of acceleration, so neither of those can be it.