Your question is 24V to 3.3V Converter Topology. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
If you need to design a circuit for a 24V to 3.3V conversion with 100uA load current and 10mV peak-to-peak output voltage ripple, what topology would you use?