I think it is because during a dive aircraft increased it's airspeed and has inertia, so for some period of time, it's trust demand will be less. I'm not sure. Maybe someone can explain more correctly.

does the question mean that the aircraft is climbing up after the dive.if so i think the thrust required would be more because it has to over come the downward inertia and change its direction to the upwward beside climbing thrust.plz correct me if i am wrong.

imagine if you are on a roller coaster..from a horizontal plane,you move upward.compare it with after you went down(dive) from the track then move upward..which one do you think require more thrust?

I have my doubts in this one.

I think because the potential energy gained from the dive supply the energy required from the climb, so you can use less thrust to go up.
I think...

After a dive you have a lot of kinetic energy so more velocity that you can spend to climb, using the excess of velocity to climb you don t have to use more power instead in level flight you need more thrust because you don t have the same kinetic energy than after a dive. Isn't it?

you already have the momentum from the dive thats why you dont have to use huge amount of thrust to take a climb.