What is the reaction force of your computer sitting on the desk?

a)the desk pushing up on the computer
b)the computer pushing against gravity
c)gravity pushing down your computer
d)friction keeping it from sliding away

When a bowling ball crashes into the pins and they fall in different directions, this is an example of:
*
a)Inertia principle in Newton's 1st Law
b)force=mass x acceleration in Newton's 2nd law
c)the action reaction principle in Newton's 3rd Law