|q⟩ Bad Qubits

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Multiple choice
Run this circuit, then measure. With what probability do you get |0000⟩?
⚛ The apparatus
const c = circuit(4);
c.h(0); c.cx(0, 1);
c.h(2); c.cx(2, 3);
// Bilateral CNOT: each party maps kept -> sacrificial on their own side.
c.cx(0, 2);   // Alice: kept q0 controls sacrificial q2
c.cx(1, 3);   // Bob:   kept q1 controls sacrificial q3
c.measure();
return c;

Commit your prediction for P(|0000⟩) — then run it.