Bad Qubits — Learn Quantum by Doing

Multiple choice

In the head-to-head comparison of Hamiltonian-simulation methods, how many ancilla qubits do product formulas (Trotter / higher-order Suzuki) require?

Zero — they use no ancilla qubits
More ancillas than LCU or qubitization
O(log L) for an index register, like the algebraic methods
One ancilla per Hamiltonian term