The answer is folded mountains.
As she pushed two pancakes together, this indicate the motion of plate materials being pushed towards each other under compressional force, which would then cause the crust to be uplifted and start to buckle and creases under the force. Therefore it is fold mountain that she was modelling.
Let's also look into the other answers:
Volcanic mountains
- Although the mountains formed under compressional force can possibly be a volcanic mountain depending on the magma movement under its crust, the modelling of pancake cannot indicate the movement of magma or represent any signs that it is an volcanic mountain with volcanic activity. Thus this is false.
Tilted fault block mountains
/lifted fault block mountains
-Block mountains are formed under tensional stress where the two plate  materials are being pulled apart and caused faulting, some rock materials will fall while causing some to be uplifted. These uplifted mountains are called block mountains. These options are therefore incorrect.
Hope it helps!
