What is the Second Law of Newton?

Whenever a force acts on a body, it produces an acceleration in the direction of the force that is directly proportional to the force but inversely proportional to the mass.
The net force applied to a body is equal to the temporal variation of the momentum of that body.
If a body is in motion, it will remain in motion with constant velocity unless acted upon by an external force.
a) Only the first statement is correct.
b) Only the second statement is correct.
c) Only the third statement is correct.
d) The first and second statements are correct.