Subject: Does exhaust hitting the ground help a rocket take off?

The engine emits exhaust and the exhaust exerts an equal and opposite force on 
the rocket, causing an rocket to lift off and thrust when it already is in 
space.  I know this.  However, I want to know if there is technically more than 
one answer to the question below:

A question on an old NY State Regents exam stated "A rocket's engine thrusts it 
into space because"
(1) the exhaust exerts a force on the ground
(2) the exhaust exerts a force on the air
(3) every action has an equal and opposite reaction
(4) energy and mass are conserved

I explained to my class that the thrust is caused by the exhaust exerting a 
force on the ROCKET.  This answer in NOT there.  Therefore, the only answer is 
(3)  every action has an equal and opposite reaction which describes Newton's 
3rd Law in general.  

One of my students vigorously complained that answer (1) also is correct:
(1) the exhaust exerts a force on the ground

What I want to know is: If the rocket is launching into "space" from near the 
ground, does the build-up of heat and pressire from the exhaust exerts a force 
on the ground help the rocket rise.  In other words, should I give the student 
credit for this question because choice (1) does contribute to the liftoff 
thrust?

Thank you.

MRP

Re: Does exhaust hitting the ground help a rocket take off?