I agree with 212. The effective change in rrpm will have a miniscule effect on pitch attitude, totally swamped for instance by the rolling resulting from disc flap-back as the aircraft yaws violently and presents the side of the disc to the forward airflow. Thinking along the same lines I woud say it would pitch nose down at that point because the cylic position was set to overcome the flapback whilst pointing ahead, but with the yawing its now pointing into a reduced (or zero) airflow. Less flapback for a given cyclic position will cause a marked nose down pitch. As 212 says, after the initial yaw all hell is likely to break loose.
Regarding CYHeli's comment, of course the effectiveness of the vertical stabiliser depends on the model, but I think that most of us would not expect to be able to maintain control short term following loss of tr drive (as opposed to following loss of tr control, where a number of models have some sort of device to set the tr to a sensible position when cables break etc). Vertical stabilisers are generally designed to add yaw stability and perhaps to unload the tail rotor in fast forward flight, but not to replace it.
Sounds to me like the question was set by someone who had not only not experienced the failure, but in fact by someone who has never flown at all!
HC