TDSM 7.1

According to Occam's Razor principle, the simplest explanations are the best. In the question it is stated that Quantum physics is much more complicated than Newtonian physics, so out of these two, Newtonian physics passes the Occam's Razor test. However for argument sake one can say that because Quantum physics is much more complicated than Newtonian physics doesn't imply that Newtonian physics is simplest. So none passes the Occam's Razor test in that case.

Pay attention! The premise to Occam's Razor principle is that two explanation can explain the same one occurrence both successfully. I'm not a physicist and I don't know if Quantum physics can explain more occurrences than Newtonian physics or there are some occurrences that Quantum physics can explain and Newtonian physics cannot and some occurrences Newtonian physics can explain but Quantum physics cannot. However, for the problem which Quantum physics and Newtonian physics both can explain clearly and successfully, you'd better use Newtonian physics. Also, for those problem that Quantum physics can explain but Newtonian physics cannot, it's nonsense to discuss the Occam's Razor principle, you have no choice but use the Quantum physics.