A is the correct answer. Hard to explain without a diagram...ill try. A horizontal gyro means that the spin axis is the horizontal axis. If you were standing at the equator with the equatorial line running under your feet front to back so you were facing west or east then if you looked at the horizontal gyro in front of you it would be rotating either to east or west and the actual axis would be running north to south. You have to remember here that the gyro does not topple as such, it's apparent topple.It appears to topple, but it is actually the earth moving that gives it that appearance..the gyro has infact remained stationary.
So our axis is pointing north.The world is turning at 15 deg an hour in the exact direction of west. A gyro and its axis are always at right angles, so if its ligned up with the meridian, then the gyro has to be spinning either west or east in direction. Therefore the axis is pointing North and no matter how many times the earth rotates it will always be in line with the meridian, and therefore no drift or topple....sounds complicated i know, but hope it helps
